My AV is running but where some previous trainers were initially blacklisted in which I had to put them into the whitelist, no such thing happened to this trainer so that can only mean that as far as my AV is concerned, this trainer is clean/non-threat and allowed to run.

As for running the trainer as admin, I'm already running my PC under my own account with admin privileges so I don't think that's the issue either.

That and the game crashes from time to time. One thing that seemed to delay such crashes was for me to make manual saves from time to time but even that only went so far before the game inevitably crashes, and then when the game is restarted with the trainer running, the game options e.g. Continue, New Game, etc. cannot be highlighted. The game had to terminated and be run again without running the trainer before it works normally again. Having to CtrlAltDel every time crashes happen gets bothersome after a while and that's not including concerns on system stability.

Any ideas on how I can address these issues or are these issues caused by code update shenanigans by Rebellion?

The information on how to run a trainer is given for a reason. If you decide not to do so knowingly you might run into issues.

As for your AV. Every trainer you download from Cheat Happens is pre-scanned and 100% free of viruses, malware or ad-ware. So creating one folder and put all our trainers in it and whitelist the whole folder in your AV is a good idea.

Have you visited our Trainer Troubleshooting Guide?

Link

As mentioned earlier, no problem with AV since the last trainer that was initially blacklisted but worked totally fine when whitelisted was Space Hulk Deathwing. This trainer wasn't even listed as having problem. If it was blocked, the other functions that worked like stealth, unlimited focus, accuracy, etc. wouldn't have worked at all.

As for running as admin using "Run as Administrator", actually I've already tried that before notwithstanding my admin privileges. Nope, still crashed.

As for the rest of the listed common problems, none of them apply. I'm even using my offline key.

Any ideas?

Do not forget to run the trainer as administrator and:

Numpad 7: Stealth (before map load)
Numpad 8: Accuracy (before map load)

Those two can be activated @ main menu, after pressing F1...duh

Note: Windows XP and Windows 10 are not supported by the game sold thru Steam