I recently updated my Blocksy theme. All of my conditional blocks stopped working after the update. Looks like the culprit is likely the companion plugin: Blocksy Companion (Premium) version 2.0.26.
Unfortunately a manual update of loading the previous version of the theme and plugin via ftp has not fixed the problem.
I tested the free companion plugin and couldn't reproduce a problem with the Conditional block, it continued to work as expected.
You can log in to the test site I created here: hidden link
Visit the "Thing" post Something on the front end and you'll notice "First Choice!" is output, which is inside a conditional (you can check the Content Template to see how it is set up).
I tried both with a slightly older version of the plugin, and the current 2.0.26 version.
Could I ask you to add the premium version there for testing, and to see if you can reproduce the problem?
I was having some trouble reproducing the same result, but it was effecting my site with all extra plugins turned of and all of my own PHP snippets turned off.
Fortunately there has been another Blocksy update and it seems to work fine.
