Red pain intensity carries over to intermission
Simply put, if your screen is red-tinted from taking damage and the match ends while that screen tint hasn't completely faded out yet, then the intermission screen carries over that tint until the game moves on to the next map. This bug might also hold true for other items that cover the screen in coloured tints, such as item pickups and the radiation suit. This doesn't seem to happen on single-player.
This commit fixes your issue.
I take it only happens in 8bpp ?
I have committed a fix to reset the palette and blending overlay upon changing to the intermission screen. This should address the issue in both 8bpp and 32bpp modes.
Since it seems to be fixed here : https://github.com/odamex/odamex/commit/6a6383b0c84c3d704aba693a5f252f44156d4c5e, please close this ticket !