Little bit of expansion when bright

[lnx64]

I noticed that my Samsung, expands a little bit when the picture gets brighter. It's not by a lot, but it does it a little.. Is that ok? I noticed my Hitachi doesn't noticeably do it, but a 27" SHARP I have (2000's era), does it too..

I don't remember the old flyback transformer too much, but I don't think it did it, but it might have too.. Been a while since I seen the old transformer.