Gmail is threading emails and completely changing the header

[thelefflaNA]

I have a weird issue where emails are threading in gmail when sent from Iterable and sparkpost.

[nicolemerlin]

Hi @Jakestreeteasy, so do they have different subject lines?

[thelefflaNA]

Hi @Jakestreeteasy, so do they have different subject lines?

Yup, things we have gone through:
There are different message headers being passed,
Different SLs
Different reply to addresses.
Seems to only be happening on Iterable with sparkpost
Iterable without sparkpost: no issue
Other ESPs deployed with sparkpost also not happening.

[hteumeuleu]

It would help tremendously if you had reproducible examples. Can you share any code?

[thelefflaNA]

The only thing I can really share is the .eml file Sincetha contains information you could have gotten by sending yourself the email.

I have tried all the "fixes" I am aware of for adding space to the preview text, and this only happens after the email deploys into Gmail threads on the third send.

Updates to Your Saved Search - 2_23_23 (2).zip

[thelefflaNA]

To give some additional context.
The preheader exists within the emails and is hard coded above the content, if a user gets another update the threaded email preview text changes to code further down in the email

[sshahs]

It appears your subject lines are the same on each send?

Also, try turning off the 'Conversation view' option in Gmail: