diff --git a/src/chat.rs b/src/chat.rs
index bee6ec022..1e7c6d192 100644
--- a/src/chat.rs
+++ b/src/chat.rs
@@ -33,6 +33,7 @@ use crate::ephemeral::{Timer as EphemeralTimer, start_chat_ephemeral_timers};
 use crate::events::EventType;
 use crate::location;
 use crate::log::{LogExt, error, info, warn};
+use crate::logged_debug_assert;
 use crate::message::{self, Message, MessageState, MsgId, Viewtype};
 use crate::mimefactory::MimeFactory;
 use crate::mimeparser::SystemMessage;
@@ -1339,14 +1340,18 @@ impl ChatId {
 
         let mut ret = stock_str::e2e_available(context).await + "\n";
 
-        for contact_id in get_chat_contacts(context, self)
+        for &contact_id in get_chat_contacts(context, self)
             .await?
             .iter()
             .filter(|&contact_id| !contact_id.is_special())
         {
-            let contact = Contact::get_by_id(context, *contact_id).await?;
+            let contact = Contact::get_by_id(context, contact_id).await?;
             let addr = contact.get_addr();
-            debug_assert!(contact.is_key_contact());
+            logged_debug_assert!(
+                context,
+                contact.is_key_contact(),
+                "get_encryption_info: contact {contact_id} is not a key-contact."
+            );
             let fingerprint = contact
                 .fingerprint()
                 .context("Contact does not have a fingerprint in encrypted chat")?;
diff --git a/src/context.rs b/src/context.rs
index 1f70efd57..5c1a1e186 100644
--- a/src/context.rs
+++ b/src/context.rs
@@ -27,6 +27,7 @@ use crate::events::{Event, EventEmitter, EventType, Events};
 use crate::imap::{FolderMeaning, Imap, ServerMetadata};
 use crate::key::{load_self_secret_key, self_fingerprint};
 use crate::log::{info, warn};
+use crate::logged_debug_assert;
 use crate::login_param::{ConfiguredLoginParam, EnteredLoginParam};
 use crate::message::{self, Message, MessageState, MsgId};
 use crate::param::{Param, Params};
@@ -660,8 +661,16 @@ impl Context {
     /// or [`Self::emit_msgs_changed_without_msg_id`] should be used
     /// instead of this function.
     pub fn emit_msgs_changed(&self, chat_id: ChatId, msg_id: MsgId) {
-        debug_assert!(!chat_id.is_unset());
-        debug_assert!(!msg_id.is_unset());
+        logged_debug_assert!(
+            self,
+            !chat_id.is_unset(),
+            "emit_msgs_changed: chat_id is unset."
+        );
+        logged_debug_assert!(
+            self,
+            !msg_id.is_unset(),
+            "emit_msgs_changed: msg_id is unset."
+        );
 
         self.emit_event(EventType::MsgsChanged { chat_id, msg_id });
         chatlist_events::emit_chatlist_changed(self);
@@ -670,7 +679,11 @@ impl Context {
 
     /// Emits a MsgsChanged event with specified chat and without message id.
     pub fn emit_msgs_changed_without_msg_id(&self, chat_id: ChatId) {
-        debug_assert!(!chat_id.is_unset());
+        logged_debug_assert!(
+            self,
+            !chat_id.is_unset(),
+            "emit_msgs_changed_without_msg_id: chat_id is unset."
+        );
 
         self.emit_event(EventType::MsgsChanged {
             chat_id,
diff --git a/src/receive_imf.rs b/src/receive_imf.rs
index fe980d52a..77da645eb 100644
--- a/src/receive_imf.rs
+++ b/src/receive_imf.rs
@@ -31,6 +31,7 @@ use crate::key::self_fingerprint_opt;
 use crate::key::{DcKey, Fingerprint, SignedPublicKey};
 use crate::log::LogExt;
 use crate::log::{info, warn};
+use crate::logged_debug_assert;
 use crate::message::{
     self, Message, MessageState, MessengerMessage, MsgId, Viewtype, rfc724_mid_exists,
 };
@@ -3835,7 +3836,11 @@ async fn lookup_key_contact_by_fingerprint(
     context: &Context,
     fingerprint: &str,
 ) -> Result<Option<ContactId>> {
-    debug_assert!(!fingerprint.is_empty());
+    logged_debug_assert!(
+        context,
+        !fingerprint.is_empty(),
+        "lookup_key_contact_by_fingerprint: fingerprint is empty."
+    );
     if fingerprint.is_empty() {
         // Avoid accidentally looking up a non-key-contact.
         return Ok(None);
diff --git a/src/securejoin.rs b/src/securejoin.rs
index c77968544..4cba5407e 100644
--- a/src/securejoin.rs
+++ b/src/securejoin.rs
@@ -16,6 +16,7 @@ use crate::events::EventType;
 use crate::headerdef::HeaderDef;
 use crate::key::{DcKey, Fingerprint, load_self_public_key};
 use crate::log::{error, info, warn};
+use crate::logged_debug_assert;
 use crate::message::{Message, Viewtype};
 use crate::mimeparser::{MimeMessage, SystemMessage};
 use crate::param::Param;
@@ -32,9 +33,10 @@ use qrinvite::QrInvite;
 use crate::token::Namespace;
 
 fn inviter_progress(context: &Context, contact_id: ContactId, progress: usize) {
-    debug_assert!(
+    logged_debug_assert!(
+        context,
         progress <= 1000,
-        "value in range 0..1000 expected with: 0=error, 1..999=progress, 1000=success"
+        "inviter_progress: contact {contact_id}, progress={progress}, but value in range 0..1000 expected with: 0=error, 1..999=progress, 1000=success."
     );
     context.emit_event(EventType::SecurejoinInviterProgress {
         contact_id,
diff --git a/src/test_utils.rs b/src/test_utils.rs
index 19f1729ad..7dd332d81 100644
--- a/src/test_utils.rs
+++ b/src/test_utils.rs
@@ -754,7 +754,7 @@ impl TestContext {
     pub async fn add_or_lookup_address_contact(&self, other: &TestContext) -> Contact {
         let contact_id = self.add_or_lookup_address_contact_id(other).await;
         let contact = Contact::get_by_id(&self.ctx, contact_id).await.unwrap();
-        debug_assert_eq!(contact.is_key_contact(), false);
+        assert_eq!(contact.is_key_contact(), false);
         contact
     }
 
diff --git a/src/tools.rs b/src/tools.rs
index cb37bdeee..3910a4766 100644
--- a/src/tools.rs
+++ b/src/tools.rs
@@ -801,5 +801,17 @@ macro_rules! ensure_and_debug_assert_ne {
     };
 }
 
+/// Logs a warning if a condition is not satisfied.
+/// In non-optimized builds, panics also if so.
+#[macro_export]
+macro_rules! logged_debug_assert {
+    ($ctx:expr, $cond:expr, $($arg:tt)*) => {
+        if !$cond {
+            warn!($ctx, $($arg)*);
+        }
+        debug_assert!($cond, $($arg)*);
+    };
+}
+
 #[cfg(test)]
 mod tools_tests;