The engines only provide numerical evaluations and different engines have different values to denote what mate is. The interface has to convert those values to mate in X.
Each engine also defines it's top non-mate value. In a quick look, it may be Komodo that does 250 as a winning is inevitable but it doesn't yet see mate in X
I have used engines since I started playing chess seriously, and I have done my fair share of work with them, but this is odd.
If there is a line that will force mate you'll get a score such as "M11" meaning mate in 11 moves at minimum is forced with best play from both sides. If there is no mate within the depth the engine can search, you'll get a score like +/- 64. The max I have ever seen was around a 64 point advantage - until today.
I received a +250 score the other day which seems odd to me. I don't think a computer is able to reach that number without finding a mate - it's mathematically impossible using any algorithm I've ever seen and it's odd that this is a higher score than the M11 in my second screenshot.
In my experience when you have a mate, it's standard to assign it a ridiculously high score to bump it to the top of the suggestions and replace it with the number of moves until mate in UI later. The weird thing here is that in the second screenshot there is no mate so this is likely not the problem.
My other ideas are this could be a problem in the engine's algorithm or simply with the logic to display the scores, but I cannot reproduce this in any other game or with this game. This only happens on the Android mobile app
So my question would be is this a bug in the app? I have looked at this game on other engines and I do not get this ridiculous score. I have also used the analysis here on chess.com via the web and do not see this which leads me to believe this is a bug in the Android app.
If there is another explanation please let me know, I'm curious how I got this weird score.