syncState is subscribed to io.lotus.call_state, which the fork pushes on every speaking/level change (multiple times per second in an active call), and it unconditionally calls setSpeakers(new Set(...)). A fresh Set is never reference-equal, so React re-renders CallStatus → MemberSpeaking + MemberGlance (which recomputes avatar mxc URLs and getMemberName per member) on every push, for the entire duration of the call, in the persistent app-wide status bar. The two MutationObservers in this file and in useRemoteAllMuted also stay attached to the whole EC document with attributes: true even when the fork path is active, so every EC style/class mutation runs a mutations.some(...) scan on the host main thread.
How to trigger
join a call with 3+ participants talking and profile the host; CallStatus re-renders continuously.
Suggested fix
bail out when the derived set is equal to the previous one (setSpeakers((prev) => sameSet(prev, next) ? prev : next)), and skip attaching the DOM MutationObserver once getLotusParticipants() has returned a non-empty list.
Filed from the September 2026 client audit (branch lotus @ 4bea4895).
**Severity:** medium · **Type:** performance · **Confidence:** high
**Location:** `src/app/hooks/useCallSpeakers.ts:43-56,114`, `src/app/features/call-status/CallStatus.tsx:28,54-72`
### Problem
`syncState` is subscribed to `io.lotus.call_state`, which the fork pushes on every speaking/level change (multiple times per second in an active call), and it unconditionally calls `setSpeakers(new Set(...))`. A fresh `Set` is never reference-equal, so React re-renders `CallStatus` → `MemberSpeaking` + `MemberGlance` (which recomputes avatar mxc URLs and `getMemberName` per member) on every push, for the entire duration of the call, in the persistent app-wide status bar. The two MutationObservers in this file and in `useRemoteAllMuted` also stay attached to the whole EC document with `attributes: true` even when the fork path is active, so every EC style/class mutation runs a `mutations.some(...)` scan on the host main thread.
### How to trigger
join a call with 3+ participants talking and profile the host; `CallStatus` re-renders continuously.
### Suggested fix
bail out when the derived set is equal to the previous one (`setSpeakers((prev) => sameSet(prev, next) ? prev : next)`), and skip attaching the DOM MutationObserver once `getLotusParticipants()` has returned a non-empty list.
---
_Filed from the September 2026 client audit (branch `lotus` @ 4bea4895)._
jared
added this to the Audit 2026-09 · Medium & Low milestone 2026-09-12 01:51:04 -04:00
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Severity: medium · Type: performance · Confidence: high
Location:
src/app/hooks/useCallSpeakers.ts:43-56,114,src/app/features/call-status/CallStatus.tsx:28,54-72Problem
syncStateis subscribed toio.lotus.call_state, which the fork pushes on every speaking/level change (multiple times per second in an active call), and it unconditionally callssetSpeakers(new Set(...)). A freshSetis never reference-equal, so React re-rendersCallStatus→MemberSpeaking+MemberGlance(which recomputes avatar mxc URLs andgetMemberNameper member) on every push, for the entire duration of the call, in the persistent app-wide status bar. The two MutationObservers in this file and inuseRemoteAllMutedalso stay attached to the whole EC document withattributes: trueeven when the fork path is active, so every EC style/class mutation runs amutations.some(...)scan on the host main thread.How to trigger
join a call with 3+ participants talking and profile the host;
CallStatusre-renders continuously.Suggested fix
bail out when the derived set is equal to the previous one (
setSpeakers((prev) => sameSet(prev, next) ? prev : next)), and skip attaching the DOM MutationObserver oncegetLotusParticipants()has returned a non-empty list.Filed from the September 2026 client audit (branch
lotus@4bea4895).