Short audio interruption when resyncing crypt-nonce

Issue description

We're currently experiencing regular (every few minutes) short audio interruptions (~5-10 secs, bidirectional) for certain users (AFAICT those with more recent client versions). I noticed that every time this happened, the server logged the following line (with the affected user's name in it):

<W>2021-05-12 01:26:37.132 1 => <86:s3lph(1)> Requested crypt-nonce resync

Expected behavior

The crypt nonce resync (I don't have enough insight into Mumble's crypto to understand what nonce that is) should complete without audio interruption.

Actual behavior

There is a short audio interruption for the affected user during crypt-nonce resync.

Steps to reproduce

1. Use the latest Mumble client
2. Hold a conversation with someone else
3. Monitor the log while talking
4. Note that there is a short audio interruption when the server logs about "crypt-nonce-resync"

Environment

• Client: mumble master (13db7bded) on Arch Linux
• Server: murmur 1.3.0 (Debian package) on Debian buster