Litespeed cache and Lighthouse issues?

I am using Litespeed cache on my portfolio page, and I noticed some strange behaviour. For some reason, whenever I run Pagespeed or GTmetrix test I get errors. when I disable it in debug, it works. Tested both with Guest mode on and off, results are the same. also I noticed that even I left default long TTL on all cache, it does refresh it for some reason. If I try to load website few times in a row in incognito (new windows each time ofc to avoid browser cache) my server response tends to be good, but if I leave it for a few mins and try again, server load is slow. like 2-5 secs for response. I am on VPS and website is fairly small. Can someone tell me what is happening here?

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