@Albus unfortunately, this may happen. But it’s not Manychat, it’s Meta.
Meta may display things differently depending on the user’s app version and OS. Older phones and apps usually show more issues than newer, latest-versions.
I haven’t experienced this issue with Galleries yet, but I have experienced other differences.
The only thing we can do about it is test, see how big a problem it is (for example, if it affects most users or only a small percentage), and try different setups to minimize the issues.
And when you have a specific error that you found (like this one), it’s always a good idea to report to Manychat support so they can report them to Meta.
Be ready to provide Manychat with as much info as you can, including app versions on the customer’s phone - if you have it.
Hope this helps!