We're creating a Case email template but would like to re-use the previous email's subject line. However, EmailMessage.Subject as well as any other field on Email Message always returns as blank in the email.
I do not believe it is actually blank though as we've also tried using the formula {!(BLANKVALUE(EmailMessage.Subject, "Text"} which also returns a blank value in the email template's subject line.
We've checked that the profiles have both read and write access on the Subject field for Email Message so not sure why it's appearing empty. At this point we're tempted to make a hidden formula field on Cases to auto-populate with the latest email subject line (we use the standard Case Subject field for another purpose) but I'd hate to waste a field on that.
Any suggestions?
After talking to SF support we figured out what the issue is. Technically Email Message is a different object and salesforce does not currently support multiple objects being referenced in one template (see here).
So we made a hidden formula field that gets overwritten with the latest email subject and use that instead. We have a professional license so our flows are already used for other things, but thankfully we had some old workflows / field updates that we could repurpose for now.
