Hi,
Probably load on the cpu as you are using x264 software. H1 and discord must push it to the max as checking the provided log you are getting
13:33:05.133: Output 'simple_stream': Number of skipped frames due to encoding lag: 868 (27.7%)
13:33:05.133: Output 'simple_stream': Number of lagged frames due to rendering lag/stalls: 14 (0.4%)
What you can do is just for H1 if this is the only time lower the cpu preset from veryfast to ultrafast this will take it easier on the cpu when encoding but with a reduced quality.