We've experienced the same thing with our store. Seems some CSS or HTML was removed in a recent update and all of our notifications emails have random spaces, lines missing, text nearly on top of each other, etc.
Spoke with other store owners and they have had the issue as well. Hopefully, something that can be rolled back..
We spoke with support as well, they have escalated it to their higher technical support to look into it further. Our support agent was able to replicate it on their end.
It definitely isn't an issue with our modifications to the template because even reverting it back to default doesn't solve the issue.
I have spoken with three other store owners and even set up a test store with no settings/templates changes, all have the same issue, the emails are completely messed up.
Hopefully whatever they changed can be reverted because it has messed with all of our emails, not just one or two...