Blank stats
 

Is this a bug?

Not sure what to say here... assuming those guys actually did play in the seasons where they're shown with no stats, then yes I think it's a bug. Not sure what I/we can offer past that, sorry.

Somewhat similar glitchy things have happened over the years with cracked versions of the game, just in case that's a helpful angle here.

single player or multi player?

Yes, it's single player.

Well, has it happened to anybody? They played all of those seasons, that's the only thing right there. But no stat. When I go to see individual or team stats, every season is empty except the last one, where everybody supposedly played only 14 games.

Does it go away? At least records are still showing but I can't see how a team or player performed in the past.
I bought it and I am playing on steam.

I have seen some comments on Steam about that issue with a different Steam game...cannot for the life of me remember which, but it was related to the way Steam stores data in several different spots.
I'm not sure if its the same thing and its difficult to relate a sports league to the other which I think was a war type game...but you might just want to install it fresh from Steam on another device, then compare that fresh install on the other device with your install that has the league and see where there might have been some deleted or corrupted data...just a thought.

But I would lose my saves, right? I think all the saved games are on the device, not on steam.
If they are on steam, then may be it could work

Yes they are on your device...I only meant to compare the two installs and see if there is a difference.
I think though also that you can sync the two devices together and maybe that would help.