After ESA>UC switch, PIP payment gone into my bank 3 weeks early and £100 short?

Hi,

I recently completed the dreaded ESA>UC migration and by the end of it I'd emerged seemingly unscathed - I didn't have to do a WCA (which was my major worry) and so I was very relieved indeed. I got my first UC payment as predicted, correct amount and on time, on July 7th. All well and good. Or so I thought.

Today I checked my bank account and to my surprise I noticed that my monthly PIP payment, which isn't due until the 23rd, actually went in on the 10th, and is £90+ short of the usual amount I receive. So on the one hand I'm (theoretically) £600 better off in the short term sooner than I thought I'd be, but on the other hand it's over two weeks too early and is nearly £100 short. By a strange coincidence, it's almost exactly the same amount that I would have been (again, theoretically) 'better off' by under UC each month.

Is this unexpected change/drop in PIP happening to anyone else? Is it possible they've decided to change my payment day and the drop in amount is one of their infamous 'temporary payment adjustments'?

The thing is that I've had no warning whatsoever about any of this. No letter, not even a text. There's nothing about this in my UC Journal or Payments section. I'm not due a PIP review until after 2027. I did not report any changes, and I was told that migrating from ESA to UC would change nothing regarding my PIP payments and entitlement (and I've been given no official/written indication that anything would change), so what is this? Is it 'a simple mistake'?

Thanks in advance as always for any help.