I can’t reproduce the issue here.
Are you using some browser zoom or custom font size settings?
Automatic font sizing and allow zoom were set from the accessibility menu in Fennec. Same issue when these options are disabled.
This is not severe for me, I can work around this.
What device, OS and browser version are you using when you experience this issue? Have you tried with another browser?
Have not. This is a 2022 moto g power with Android 12 and Fennec 129.
Chrome will loop the gallery in the same way.