This is the second time in less than two weeks that customers have reported issues with transactions.
Ulster Bank has been made "aware" that mobile app transfers have not been appearing in the accounts of some customers.
The issue arose between 6.30pm on Monday, 30 April and 6.30pm on Tuesday, 1 May during which time, certain duplicated Mobile App transfers debited customer accounts, but did not credit the beneficiary account.
In a statement, a spokesperson for the bank said this came as a result of the European Bank Holiday on Tuesday:
"Tuesday 1st May was a European Bank Holiday, for the whole industry. Many organisations made arrangements for payments (i.e. Standing Orders and Direct Debits) due on 1st May to be paid on Monday 30th April.
"If they did not make arrangements those payments normally due into your account on 1st May will be processed on Wednesday 2nd May and will appear in your account on Thursday 3rd May."
The statement went on to say: "We are working hard to rectify this as a matter of urgency.
"If you resent a transfer to another Ulster Bank account holder via the Mobile App during these times we will reverse the duplicated debit(s) on your account as soon as possible. Please do not take any action to request the Beneficiary to return the duplicated funds, we will contact them separately."
https://twitter.com/leyanne11/status/991580720773632000
The issue comes after the bank's customers voiced concerns over the
disappearance of funds from various accounts on 24 April.
Following an investigation, a spokesperson was able to confirm that the failure to process these payment files was the result of "human error."
