My suggestion is to make a clearly and easily visible persistent indication that the bonus 2 minute time has been collected and added to the clock timer on the ui. I'm suggesting a simple golden, glittery, magic effect chasing ring(two examples below) that circles the clock timer in a clockwise direction at a comfortable pace. In addition, have a greyed out +2:00 that rests just beneath the clock timer that lights up with the same golden glow as the chasing ring when the bonus time has been collected(I imagine a quick glittery burst of golden particles with glow burst that flashes into place of the greyed out empty +2:00 bonus time placeholder – as though magically emblazoned right at the time it was collected then finishes into a static golden color as the magic ring chases around the clock timer). It's a clean and clear and it persistent visual indication that the timer was collected and players don't have to contend with all the issues of scrambling to find out or just know with a quick visual confirmation that the bonus time was collected and can just focus on the match at hand.
What exists now of just a very brief flash and fade of the text & the +2:00 number on the ui/ and the text in the chat box isn't enough because the former is not persistent and the latter gets lost in the chat and people have to dig for it and still can often be difficult to find amongst the chatter. This just ends up in a persistent asking "did we get the timer?" in every match. It's time consuming, attention/focus distracting, and can often be a derailing factor trying to find out if the bonus time was collected yet or not. It's an issue whether it's a random pug team or even a grouped up pre-made team. It's a constant source of unnecessary frustration.
I made some quick and dirty visual examples of what I'm suggesting:
