Lines in the sky

Hello everyone! Its been a while since I posted on this forum! Amazing to see how far SH5 has progressed in the last couple of years!

Just a quick query in case anyone else has seen this;

Got to re-installing SH5 last night and noticed something weird - at certain times there will be horizontal lines across the sky, going all the way up. Now It looks just like a problem I had on FSX and what I did to resolve the issue was turn on the anisotropic filtering - has anyone seen this behaviour?

Many thanks,
Sev