A/V desync only when using projector mode

Operating System Info

Ubuntu 22.04

Other OS

Ubuntu Studio 22.04LTS (real time / low latency kernel)

OBS Studio Version

Other

OBS Studio Version (Other)

30.2.3

OBS Studio Log URL

https://obsproject.com/logs/WhWl3JtuFOnoQfwO

OBS Studio Crash Log URL

No response

Expected Behavior

When using the projector mode of OBS displaying in fullscreen the captured video game console using a (Decklink) Blackmagic design Intensity pro 4K, the video and audio should stay synchronized whatever the duration of the stream/capture/recording

Current Behavior

When using the projector mode of OBS displaying in fullscreen the captured video game console using a (Decklink) Blackmagic design Intensity pro 4K, the audio is notably delayed after dozens of minutes (v30.2.3, or around 5min with v30.2.2).
The v30.2.3 update get positive impact on the audio delay but not fix it.
Note that as mentioned previsouly, the A/V desync occurs ONLY WHEN PROJECTOR mode is used. There is no A/V desync otherwise.
Because I did not capture video game console since a while, I assume this bug was introduced with one of the version 30 of OBS (my last console capture using projector was with v29, no A/V desync occurred)

Steps to Reproduce

1. Run OBS, select the scene including the capture card
2. Use the projector to project the capture card (or the full scene) in the second screen
3. play the game, and audio will desync after 10-15 minutes (v30.2.3) or less (around 5min with v30.2.2)
   ...

Anything else we should know?

HW configuration:
CPU Ryzen 3700X stock frequency, 64Go DDR4 RAM, OS disc SSD Samsung 980pro 512 Gb, GPU RTX 3060 12Gb
Decklink Blackmagic design Intensity pro 4K PCIe 4x installed on a 16x port
Video recording on a 6Tb HDD 7200rpm Seagate hard drive
Audio card: internal built in with ASRock Phantom 4 pro gaming, and USB Audio DJ 8 (no effect on the A/V desync)
2 gamer screens 144Hz compliant (Asus VG248 and MSI G2712) 1080p working in native resolution using both DP inputs

SW configuration:
Ubuntu Studio 22.04 LTS (low latency 5.15.0-118)
OBS 30.2.2 or 30.2.3, NVenc, Deckling Blackmagic design Intensity pro 4K, no buffering, downscale output 720p at 2200kbps @60fps, AAC 160kbps audio encoding
Decklink low audio latency mode tested On or Off (no effect on the A/V desync)
pulseaudio / pipewire

No A/V desync when projection is not used, even after 3h of stream/capture/recording

No source file or test is named. Start by reviewing the linked OBS log and reproducing the Decklink capture in projector mode, then compare its timing with the same scene without projection. Done means audio and video remain synchronized during extended projector use on the reported setup.