16:34:12.949: - scene 'Scene':
16:34:12.949: - source: 'Game Capture' (game_capture)
16:34:12.949: - source: 'Display Capture' (monitor_capture)
16:34:12.949: - source: 'Window Capture' (window_capture)
16:34:12.949: - source: 'Image' (image_source)
16:34:12.949: - source: 'Video Capture Device' (dshow_input)
16:34:12.949: - source: 'Game Capture 2' (game_capture)
Having a Display Capture in the same scene as a Game Capture can cause significant performance problems, even if they are not concurrently enabled; Display Capture should be avoided if at all possible, except as an absolute last-resort. If you NEED to use one, it should be in its own separate scene.
Likewise, having two Game Captures in the same scene can cause problems (but not as severe, usually). Recommend removing one.
Other than that, your logfile doesn't show any rendering delay or encoding lag, so that's the most likely cause of the chop.
Unrelated to the question:
I'd also recommend swapping from CBR to CQP or CRF, which are quality-target based encoding methods. They use as much or as little bitrate as is needed to maintain a given image quality level, so no waste on simple scenes, no bitrate choking on complex or fast-moving ones.
NEVER RECORD DIRECTLY TO MP4 FOR ANY REASON. It is NOT a recording-safe format. Record to MKV or FLV, then use the 'remux recordings' option under the OBS File menu to convert to MP4 if you need them for editing.
