1. I've updated all my child theme files. Same problem.
2. I tried the old child theme merge ... variations don't work ... like you said before.
3. Went back to the plugin and fixed the Product Details display problem with some CSS but still not happy.\
Bottom line ... sorry to say this ... but it just does not look good. Too much white space ... too scammy looking. This is the first time I've had negative feelings to any of the ALIDS plugins. I just don't like this one.
If a plugin does not work with my child theme ... then forget it. My child themes are what make my sites unique. I'm not going to sacrifice that uniqueness for any plugin. I will just look for alternative solutions.
I'm sick of it too. I think I will just promote a single product by simply using the URL to the normal product page. Looks more "honest".
OR ... I will explore some 3rd party landing page plugins that I can customise to the way I want them to look.
So ... at the moment ... I will give this plugin a miss ... unless changes are made. Like getting rid of all that terrible looking white space and the need to fill it in with background images. But that's just my opinion ... maybe others like it.