WD Quick View - Drive discovering.. Normally white icon now blincing green?

Hello!

Wd My Cloud 4 TB has, what is odd WD Quick View - Drive discovering…
Normally white icon is now constantly blincing green? It worries me.
Something wrong?

On the last few days I have backuped tens of thousands of photos and videos from My Book to My Cloud via ethernet cable. At this moment Quick View shows that My Cloud is 85% used. Is it too much?

Never before have noticed that Quick Viem Symbol blincs green.

Is there something to be worried in this case?

Thank You for all advice and hints!