Map a custom field (on any layout) to an issue field in Jira (for our purposes, other institutions will have different integrations) where the population of that field occurs in a single direction (Jira to Aha!). Once populated in Aha!, only the integration should have the ability to update it. This makes it read-only to the Aha user but amendable by the integration user. Perhaps this could be achieved with an additional choice in the mapping options (single direction, one-way edit)
The idea that "the field will be kept in sync by subsequent updates" assumes there will be updates from the development system.
If there will be no updates from the development system, the changed field will never be 'corrected'.
+1 to Russell's comment. The whole point of integrating systems like this is to expand functionality while maintaining sources of ultimate truth and "oh it'll just get overwritten later" is not really how this is supposed to work. Please re-prioritize this higher.
I hope it is understood that allowing the users to modify a field only to over-write their entry the next day is a poor design. This can potentially cause confusion and does not take into consideration the possible impact on real time reporting.
See APP-I-7145/. I just created a duplicate request.