Thanks for the suggestions, folks. Thanks @tom for suggesting the BC forum.
My understanding of the Dynamics 365 Sales CRM > Business Central Quote integration is that it is one-way and does not allow further sync, at least in our system that seems to be the case.
The Business Central "Sales Quote" card does not have the typical "Synchronize" menu options. I don't see a way to uncouple imported quotes.
Likewise, there are no integration tables for Quote entity in BC as there are for Products <> Items, Sales Order, Sales Invoice, etc.
In terms of why someone would delete the quote in BC - the system doesn't forbid this and there is no visible way to resync the quote from CRM into BC after changes are made to the quote in CRM. So the users might understandably delete them. We could take away the permission, but previously I understand this to have worked OK - someone could delete a BC quote imported from CRM, then reimport afterwards as required. So it seems like this is a recent issue arising from patch to BC v26.5
Further investigation seems to hint that:
1. It only seems to break when the CRM quote has a revision code > 0. In this scenario, CRM closes the original quote and creates a copy with incremented revision # in draft status to allow editing. The user then "activates" the quote, which makes it visible to BC. Even when someone has not previously imported and deleted in BC, if a quote in CRM has been revised then it seems it cannot be imported as it experiences the same error.
2. Non-revised quotes import fine for the same customer and user where the error manifested previously.
The workaround at the moment is to create a brand new quote instead of a revision, but this is obviously not a good long term solution.
I have checked the integration setup in BC as well as Dynamics 365 Sales CRM app versions - all are latest and test connection OK. The other integration works as expected and we have no issues with quotes that have no revision ID.
Interestingly, in the import details in BC, the close date of the quote shows from a prior revision. So I am wondering if the filtering BC uses to pull the data from CRM/dataverse is not correctly isolating the quote entry and this is where it is falling over. I've engaged with our consulting partner/reseller but was hoping to gain more info on whether this is a known issue.
Thanks again for ideas and suggestions.
