Problems since WP 5.6

Hello,
First thank you for your good job.

It seems to have a probleme since I got the WordPress 5.6 edition.
For new members (only for them), in comments of a post, the avatar is very small.
I tried with different sizes and it is always the same thing, but in forums, the size is good.
I read somwhere than WP 5.6 now uses the get_avatar() function differently.

What do you think of that ?

Geetings