Kerbal Space Program

I've gotten this as well, it seems like sometimes test contracts generate failures immediately, but are still completable. Both contracts showing failures show identical successes, and I know I only accepted 1 of each. I remember noticing the failure messages on entering the VAB to create the crafts to complete them.

This is happening with both DLCs installed, although I think it's a problem with the core game, don't see how Making History could cause it.

Sorry for possibly bad english, this is not my native language.

I reproduced this bug on Windows 7 x64.
Game version 1.7.3, clean (absolutely no mods) Steam install, no DLC.

Game generates contracts for old variants of reskinned parts (1.7.0 update), hidden from player using parameter category = none and had additional flag TechHidden = true
After these contracts are accepted, probably when scene changes, game checks for TechHidden flag and fails them.

Reproduce steps:
1) for more comfortable search rename old parts' titles in format [OLD] defaultTitle, e.g. [OLD] RT-10 "Hammer" Solid Fuel Booster //#autoLOC...
2a) start new career and complete default "Launch our first vessel!" contract
2b) or just continue existing career
3) decline new offered contracts until getting one with the [OLD] tag
4) accept contract
5) make quicksave (not necessary for reproducing, but useful for further checks)
6) go to VAB, SPH, Tracking Station or just reload quicksave
7) get contract instantly failed

Special check for TechHidden line:
8) exit game
9) comment out line //TechHidden = true in old parts' files or set it to the False value
10) start game and load the quicksave created on the 5th step
11) not get contract instantly failed

This contract is still impossible to complete, because of the line category = none, that does not allow part to appear in the Editor. If valid value is set e.g. category = Engine, contract becomes available to perform. Of course that is not needed, there are revamped parts for playing with.

Summary:
Looks like the game doesn't check parts' value TechHidden during contract generation, so that check can be added. An alternative way is to remove MODULE[ModuleTestSubject] from old parts to prevent contract generation for them.

One year have passed. We got update 1.11 already, but they didn't fix the issue. I'll try to create a new issue to see if it gets attention again.

Need more information about this one as we can't get the contracts to fail as you describe:

https://drive.google.com/file/d/1c0tbgwycqTInKP8tjYU2VxV_DseDhB0_/view?usp=sharing