If you did not know, then you did not know.
I'm assuming that this is a Phase II exemption. I'm also assuming that you reviewed their filings at your Secretary of State's web site when you did your annual review and the change in ownership was not apparent there or through review of any other dealings they may have with your bank; e.g. borrowings.
If my assumptions are correct, I don't see any basis for criticism. Either way, when you file your next required biennial renewal, check the appropriate box and go on. A change in control does not trigger a filing requirement, but it should be noted on the next form you file.
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In this world you must be oh so smart or oh so pleasant. Well, for years I was smart. I recommend pleasant.