Rapid back and forth ranking

Is Google known to “test” or allow a page to rank highly for short periods like maybe according to the algorithm you qualify to rank well for one reason but for some other reason (maybe not enough trust or something) they suppress it?

I thought semrush was just glitching because I have been swinging rank 5, 40, 5, 40 on a high traffic keyword. But when I check the USA SERP in the middle of the night, my site is on the first page. Daytime, back to about #40.

It’s a bit weird. My theory is Google is testing me out but unsure of me?

🤷‍♀️