My PPF is usually in my Thai bank on the first of every month even if the first is a Monday. If the first is a Sunday it arrives the previous Saturday. My OAP is paid four weekly therefore arrives into my IoM bank on different days ever month.
I will agree that your pension is paid every 4 weeks, or 28 days, but not on different days each month.
For example, if your pension was paid on the 1st of March, a Tuesday, it shoud be paid again on the 29th March, also a Tuesday. Last month, my pension was due on a Monday, the 21st of February, 28 days after the previous payment. However, it was not paid on that day but on the following day, Tuesday, the 22nd February. Puzzled, I Google 'Payment of State Pensions' and found the following.
On checking my National Insurance Number I discovered my due day was a Tuesday. As it happens, Tuesday is a better day than Monday and is not affected by Bank Holidays. However, delving further into the document, I found there were different rules for people living overseas.
Delays to payments around US bank holidays
If you live abroad and your payment is due in the same week as a US bank holiday, it could arrive one day late. This is because a US company processes these payments.
Indeed, there was a US Bank Holiday on Monday 21st of February, Presidents’ Day (3rd Monday in February
, Monday, February 21, so that would also explain why my payment in February was one day late. I now await with interest to see what day it is paid this month, either Monday or Tuesday, 21st or 22nd of March. My guess is that it will be paid on Monday, 21st March. I will advise later.