CRM 2019.R2 integration with Sage 300 2020: saving in CRM not always propagating to ERP

SOLVED

Am doing a test upgrade from our existing CRM 2018.R1 / ERP 300 system 2018 to CRM 2019.R2 integration with Sage 300 2020. No problems encountered in the upgrade. But doing acceptance testing, the following was discovered...

When making an edit in CRM that propagates to ERP (e.g. changing a customer's address), if you click on the text "Save", it updates CRM and propagates through happily to ERP. However, if you click the "Save image", the change is made in CRM but does NOT propagate through to ERP. This observation was encountered in all integration components and using the different available themes: Sage, Classic and Neutral. Problem is not encountered in theme: Contemporary, since it is the only one that does not have images, just the text in buttons.

Problem is encountered using both IExplorer and Google Chrome.

Ideas?