S1&2: Camera misbehaves during fire shield air dash

[Decidetto]

If S3 items are enabled from the game options in either game, when using the air dash granted by the fire shield, the camera "falls down" early before Sonic does. This happens in either game.

In the original mobile version of either game, the camera stops tracking Sonic and only starts tracking him again 15 frames (at 60 fps) after initiating the dash.
The pause in horizontal tracking is correctly reflected here, but the vertical behaviour is inconsistent.

I analysed this 60 fps YouTube video frame-by-frame to check various hypotheses: https://youtu.be/C0FQPNJOYf8. The framerate in this video is not entirely consistent, but some air dashes where the framerate does stay stable for the duration of the camera freeze are at 4:57 and 5:12.
I initially thought that vertical camera movement in the original was locked for a certain number of frames, too, but an occurrence at 5:22 debunks that, where Sonic does an air dash at ground level, where the camera tracks him vertically even during the initial horizontal camera-stop.
I've done some more research and the Sonic Physics Guide at Sonic Retro may shed more light on it: http://info.sonicretro.org/SPG:Camera#Flame_Shield.2FHyper_Sonic_Air_Dash
Having read this page, I believe vertical movement during the air dash may simply be a product of the "vertical border" rule.

My checksums (both are pre-Sega Forever):
S1 Data.rsdk MD5: 10E320E8B3C1BA3B87B1E8EE01B2492C (v2.0.8)
S2 Data.rdsk MD5: 6F1244F8D6E3822778F69BCE2D1E8558 (v3.1.5)