Looking at those examples:
Image 1: This works as expected - the tag is surrounded by parentheses and so this is a valid situation
Image 2: Both examples are as expected - you'd never use a * immediately preceding an @ tag in the first, hence not tagging. In the second, the username contains * twice and it's being tagged as expected.
Image 3: The same as the first example in image 2
(
@Mike) should behave differently to *@Mike* as it is perfectly acceptable to enclose names and other text in parentheses in various languages. Surrounding tags with * isn't something that is expected, just as I wouldn't expect 1@Mike1 or %@Mike% or enclosing a tag with any other letters, numbers or symbols to work.
It seems to me as though you are trying to find issues here which don't exist.