As far as I know Manchester United are banking on their current manager for one more season. Manchester United did not get good results under this manager yet Manchester United gave the manager another chance.
If Manchester United stick to their singular decision this transfer season, if they extend their current manager's contract for another season, I would assume this is the last chance for Ten Hag. If Ten Hag fails to deliver good performance this season, Manchester United will definitely fire this manager without thinking about next season.
Ten Hag was expected to be fire around the end of past season but Manchester United decided to continue with him at least one more season. It's not easy to say this decision is good or bad because he will have one more season to defend his coach position. Manchester United will use a next season to assess his work and at this moment, there is no enough more evidence from Manchester United to make a tough decision against Ten Hag.
But now there are rumors that Manchester United could change this manager.
Basically when the transfer window opens there are many such rumors and all kinds of rumors are likely to come true now it remains to be seen whether Manchester United will trust their old manager or hand over the reins of their club to another manager.
I see it is pure rumor, nothing more than that. If Manchester United did not sack Ten Hag months ago but oppositely decided to use him, it does not make sense to sack him now when a new season is in the air.