I used the text from your question for a google search and found a bank that used similar verbiage, but the next paragraph induced additional information:
The Account will consist of a checking sub-account and a savings
sub-account, and the Bank may periodically transfer funds between
these two sub-accounts. On a sixth transfer during a calendar month,
any funds in the savings sub-account will be transferred back to the
checking sub-account. If your Account is a plan on which interest is
paid, your interest calculation will remain the same. Otherwise, the
savings sub-account will be non-interest bearing. The savings
sub-account will be governed by the rules governing our other savings
accounts. This change will be transparent to you and will not affect
your statement, any terms and conditions of your account, or any other
items in your account.
My concern would be "why are they doing this?" They will be moving funds behind the scenes to make it appear they are meeting federal regulations even when they aren't. It also appears with this bank that the savings accounts don't earn interest, but to be fair 1/10 of 1% is almost zero.
note: I have no idea if this applies to your bank, but I did find this explanation interesting.
regarding the sixth transfer:
The concept of the sixth transfer is interesting. If they decide that the customer with 10K in checking really should be 1K in checking-subaccount and 9K in savings-subaccount, but then they write a check for 5K, the bank will behind the scenes move the money back to the checking-subaccount. Thus using one transfer. Since they have to limit the transfers to six, or charge the customer they will then have to move all the funds back to the checking-subaccount for the rest of the month.