Normal for krausen to form in slurry jar?

I got some yeast slurry from a local brewery last week, but wasnt abke to use it right away. It was just put into a sanitized mason jar with star san. The owner told me it was real active and to be careful with it. It was mostly yeast with a little beer mixed in and they slowly separated more and more over the first few days.

I put it in the fridge and relieved the pressure on it once or twice a day. About two days into it, it seemed to form a krausen at the top and still has some floating.

This surprised me quite a bit ... I know he called it active, but still didnt think at refrigerator temps it would still keep going (its an ale yeast).

Has anyone seen this before?

Is this normal? Any concerns? It is wlp041 if that matters.

I think it's normal, I topped cropped some yeast from an open fermenter which was quite active. After it settled, I decanted a good amount of liquid off and replaced with with sanitized water. I am not sure if this is best practices or not, but I was left with a good amount of white yeast.