The biggest problem we have seen with split in Lacerte is probably DCB exclusion because Intuit misunderstood the application before but I recall that had already been fixed.

Having the totals being equal on the MFS returns vis-a-vis MFJ doesn't mean a thing.  The MFS returns could be grossly incorrect depending on (1) how you have coded T/S/J for each item and (2) whether those spouses are domiciled in community property states.

The key is to code T/S/J correctly (because that's what drives the split), check the MFJ vs MFS comparison carefully (which is always the first step for optimization), and cross-check the MFS returns after the split.

"Learned of this when client brought IRS notice in. Will correct by amending returns and profusely apologizing to client. Trusted the software once again!"

It is each tax professional's responsibility to review the return and sign off on its completeness and accuracy - that's in Circular 230.  If there's a mistake I didn't catch, first and foremost, that's my fault.  The last I checked, faulty tax logic in the tax software doesn't count reasonable cause.  If that mistake was caused by a bug, you have every right to expect a fix but, to me, that's a separate issue.