Bank Transfer - Am I Too Suspicious?

[Citroënbender]

Not a regular “Have I just been scammed?” type scenario.

Long story short, a customer owes me quite a bit; their first invoice. They indicated yesterday morning, they’d transferred the sum, I received an email and barely glanced at it.

As no payment was credited overnight, I looked harder at the email to confirm my correct account details. Yes, tick. But the email wasn’t actually payment advice, but a copy of a bank email sent to them saying “Payee information updated”.

I’ve let it rest for today, but wondering if they have done this to buy time, so it looks like they sent payment the other day but in fact deferred restitution (presumably to fall in with their own finances) and will credit me today or over the weekend…

Anyone experienced something like that?