Spectra Blocks and SiteGround cache issue

Hi

Since last update Spectra 2.12.1 all pages break, images do not load, sliders fails, etc

It occurs when Speed Optimizer is activated and Frontend > CSS and Frontend > JS enabled.
If both options are disabled the site runs properly.

Thanks

PS: Tickets comes from https://wordpress.org/support/topic/siteground-cache-issue/