Bad sound with Opus codec on T21 and T40

[TrK]

I have several T21P E2 and T40P phones with latest firmware 82.0.20, Asterisk 14 (FreePBX 14 actually, installed with Asterisk 13, upgraded to Asterisk 14 with asterisk-version-switch) and lot of W56 handset (no Opus support yet). I use Asterisk PJSIP driver for my Yealink phones.
Opus was enabled everywhere and also set as primary codec. Asterisk console show calls established using opus (with opus->slin and slin->opus conversion actually).
In phones Opus enabled with autoprovision:

Code:

account.1.codec.opus.enable = 1
account.1.codec.opus.priority = 0
account.1.codec.opus.rtpmap = 107

But voice sound as ... corrupted? Some scratches and crackles, you know.
First I blamed bad network connection, but it was not true - even phones in same LAN have this issue.
I tried to update Opus - download latest codec from Digium and install it to Asterisk. No luck, voice still bad.
I tried to disable Opus in PBX and replace it with G722 - sound become much better!

Should i stay with G722 for now or die trying try to solve this issue somehow?