mirabeau

I ran into the same issue tonight, and the only way out of it was to save Brian_J's provided text frame in my assets panel (tip'o'the'hat to you!). Column width, insets, none of this made any difference. I'm about ready to submit a Bug Report.

FWIW, I have not avoided it & have had no issues that reasonably could be traced to using it.
Actually, it does. See for example the "Select the information to transfer" step in this Apple support document. 

Click on your name on the upper right of the forum window, which will expose some options. Choose Account Settings, and then Signature in the left navigation options.

Yep, your asset behaves in my app the way it does in yours. (Open your asset, make my own asset from it, delete yours, place mine.) I was even able to drag a 2d asst in (an "open quotes" at 96pt. which I use for my pull quotes), and the text wrapping between the two kicked right in.
The effect I was describing was identical to a .pdf import WITHOUT "group lines of text into one text frame". And while this glitch wouldn't let go, even copying new text to a new frame, earlier MON, I had trouble getting it to misbehave to make the file I originally uploaded.
I get the hint <G>: Publisher wants me to upgrade to the minimum 10.12 (this machine is 10.11). That'll happen when my new Mac Air arrives (…been on order for a month, and Apple is still looking for the chips to make it with).
 
 

You've been mentioned over on the Luxology (Now the Foundry) Modo forums. That's how I found out about this software.