syncprov olcSpNoPresent not being honoured

Hi, I have an OpenLDAP server I'm upgrading from 2.4.58 to 2.6.0. The server is configured with the syncprov plugin, with "olcSpNoPresent: TRUE". Previously, on 2.4.58, we would never see any Present phase data originating from the server. However, post upgrade, we are seeing this, and it's causing problems with the consumers. I've tried looking at the code, but I must admit I got lost trying to trace through the propagation of this flag. Are there undocumented circumstances where olcSpNoPresent will not be obeyed, or is this a regression? Thanks! Lisa