The behavior for that seems slightly different. It’s possible it was a bug that was already fixed too (or buggy extension even). but, I did originally think that. It’s not a big deal, and only noticed it recently.
But even after reading it, it seems it needs to be a deliberate action, not automatically grouping. In the more general support page for tab groups (linked at the bottom of that page), mozilla says AI enhanced tab groups started in version 141.
The behavior for that seems slightly different. It’s possible it was a bug that was already fixed too (or buggy extension even). but, I did originally think that. It’s not a big deal, and only noticed it recently.
It could be related to this https://support.mozilla.org/en-US/kb/how-use-ai-enhanced-tab-groups
But even after reading it, it seems it needs to be a deliberate action, not automatically grouping. In the more general support page for tab groups (linked at the bottom of that page), mozilla says AI enhanced tab groups started in version 141.
It could be a bug.