Occupant sorting is now done by ConverseJS:

It was a bug, i made a PR on ConverseJS to fix it.

conversejs/build-conversejs.sh

@@ -15,7 +15,8 @@ CONVERSE_COMMIT=""
 # - #converse.js/3300: Adding the maxWait option for `debouncedPruneHistory`
 # - #converse.js/3302: debounce MUC sidebar rendering
 # - Fix: refresh the MUC sidebar when participants collection is sorted
-CONVERSE_COMMIT="4861395f047e4abee2b30271c80d29a86baf7828"
+# - Fix: MUC occupant list does not sort itself on nicknames or roles changes
+CONVERSE_COMMIT="64d23bd160a9531c45604b1d7e86b4c759a1e883"
 CONVERSE_REPO="https://github.com/JohnXLivingston/converse.js"
 
 rootdir="$(pwd)"

conversejs/builtin.ts

@@ -121,20 +121,6 @@ window.initConverse = async function initConverse (initConverseParams: InitConve
               // To mitigate this, will don't display nickname changes if the previous nick is something like
               // 'Anonymous 12345'.
               if (/^Anonymous \d+$/.test(nick)) {
-                // We are sorting anonymous users at the end, by overriding ChatRoomOccupants.comparator.
-                // But this has a caveat: occupants are not sorted again when nicknames changes...
-                // As a workaround, we re-sort the occupant list here, when we intercept a action info message
-                // from an anonymous user that has changed his nickname.
-                // FIXME: This is not very clean... but will do the work.
-                try {
-                  // Moreover, we can't sort now, as the new nickname is not saved in the Collection...
-                  // So using a setTimout
-                  // FIXME: find a better way
-                  setTimeout(() => this.occupants.sort(), 100)
-                } catch (err) {
-                  console.error(err)
-                }
-
                 // To avoid displaying the message, we just have to return an empty one
                 // (createInfoMessage will ignore if !data.message).
                 return null