16:45:18.578: Output 'adv_file_output': Number of lagged frames due to rendering lag/stalls: 41 (1.6%)
16:47:57.776: Output 'adv_file_output': Number of lagged frames due to rendering lag/stalls: 17 (3.2%)
16:54:43.210: Output 'adv_file_output': Number of lagged frames due to rendering lag/stalls: 32 (3.1%)
The AMF encoder on AMD cards is not "free", exactly, like NVENC on Nvidia cards. You're slightly overloading your GPU, and OBS warns of this almost immediately:
16:54:12.272: [AMF] <Id: 29> No output Packet, encoder is overloaded!
16:54:12.349: [AMF] <Id: 29> No output Packet, encoder is overloaded!
16:54:40.051: [AMF] <Id: 29> No output Packet, encoder is overloaded!
16:54:40.149: [AMF] <Id: 29> No output Packet, encoder is overloaded!
I'm not familiar with the AMF settings, but you incur the most load when doing 1080p60, which some of these sessions are.
If your streaming and recording settings are different, (one scaled, the other not) then you're using two encoding sessions on the GPU, plus the load of the application you are capturing. This may not be tenable on that hardware.