Hi Damir,
Sorry for the delay.
CopyToResolveTarget doesn’t really have the capability to clear anything. It could overwrite the target texture if the source and target were different, but from the looks of FTextureRenderTarget2DResource::InitDynamicRHI they should be the same.
Can you confirm that in the CopyToResolveTarget call in question the source/dest are the same? If they are then the problem is elsewhere. Some other rogue clear or draw coming in before or later.
Are you specifically seeing it cleared to green? A breakpoint in RHIClear or SetRenderTargetsAndClear around the problem area should help narrow it down.