Hi all, I had this issue too. Though not a permanent solution, I found that when I selected the items in indesign and/or changed the preview mode to high quality it made a high quality jpeg. If I kept the file at typical quality I got the jagged edges. Go figure, I hope they fix the issue soon, I don't really want to be changing everything to high quality every time before I export. Not a very productive way to work.
We have concluded our investigation into the issue and found that the issue is specific to few versions of MacOS 10.14.×.
As a part of our investigation we had reached out to many of you, where many of you have confirmed that the issue gets resolved after upgrading to MacOS 10.14.5.
If you are NOT using MacOS 10.14.5 and still facing this issue, please upgrade your MacOs to 10.14.5 version.
In case you continue to face the same issue after the upgrade, you may reach out to us at firstname.lastname@example.org.
For any other problem related to packaging workflows please create a new thread.
We are closing this thread for now.
Thank you for your patience all this while.
Will there be a fix soon. I can't even export to jpeg or png from Indesign.
Same issues here too, since updating to Mojave. Have gone back a few versions of Indesign so as not to stop my workflow. I have also found that the same issue occurs when exporting to jpeg or png, it goes through the motions but no result at the end, works when saving locally though.