[ARM] Grouped accounts not reopening after change made to a prior period

An entry was made to two accounts, for December, among others, which we have grouped as "Intangible".  One account increased and the other decreased, but the total for the grouping did not change. The recon, previously closed, remained closed.  Is that expected?  Was thinking that the recon should be re-opened due to the change.

Thanks in advance!