Error with "Login Widget with Shortcode"

Please see this FAQ:
https://www.ads-software.com/support/topic/faq-what-is-causing-unexpected-tokencharacter-syntax-error

Did this FAQ resolve your issue?

Unfortunately not, I’ve no control over the apache modules installed by my ISP (SiteGround)!

So the issue was mod_sec?

I suspect that, yes!

Ok. I’ll leave this ticket open as technically it’s unresolved, but I still have no idea what aspect of mod_sec is the problem. (or rather: what aspect of Loco it doesn’t like). It’s on my very long todo list to find out.