You probably deactivated the warning sent by the browser for these protocol handlers. You need to check your browser settings.

What trades are you trying to create?

Try CTRL+F5.

There are no exceptions, one may not ask for donations under any circumstances. Like it has already been said, if you are a true collector people will donate items regardless of whats in your trade notes.

Allowing this would give a green sign for everyone to create weird/pointless trades and embed that sentence just to get free items. And a lot of subjectivity would come in place while dealing with a related report.

Początkowo opublikowane przez Generic:

but will they be fixed in the future?

That's a question you need to ask Valve.

https://steamhost.cn/steamcommunity_com/groups/tf2outpost/discussions/17/666826069046046070/

No PC here, read the rules.

Enter "Any TF2 Item" in the search box.

This is not an issue, it works as expected.

This is not a bug, moving to discussions.