Barclays GM Card, new account setup oddities after hand off from Marcus (Goldman Sachs)

I have a GM Credit Card since/from the early 1990s. GM recently handed off the credit cards from Marcus, a CC brand name used by Goldman Sachs, to Barclays.

The actual, official handoff date was 25 August 2025 per multiple hardcopy mailings and emails from GM & Marcus.

I received and activated the new Barclays branded GM Card and created an online account. Everything fine so far. In fact, extra credit goes to Marcus and Barclays for making Marcus PDF statements available back one year, directly from the new Barclays online account. Maybe that's normal but I never saw this before.

The oddity: When I added the new Barclays account (early September, a few weeks after the cut over date), the opening balance transaction is dated 20-Jan-2025. I would have expected this to be some date in August 2025, because the Marcus card was active and usable through 25 August.

The additional oddity, I have two additional entries, dated 21-Jan and 13-Feb, one for a charge and one for a payment. Both these two entries were in the Marcus account when it was active, and both were cleared and reconciled.

I don't get how there can be such obvious mistakes in this — account entries dated eight months before the account actually existed. You'd think there would be rules and checks against something like this.

This is mostly a rant and observation.

I only have one question in this, do I modify the opening balance transaction date to show the actual opening date, or do I leave it as is from what was populated in the account setup process? I already voided the two transactions because they were duplicates and already existed in the Marcus account.