About the child theme, what you are experiencing is a race condition. Sometimes your css is loaded first and sometimes after the plugin’s css. Normally as a programmer when you enqueue stylesheets in WordPress you can specify a graph of dependencies between various assets so that this does not happen. In this case, the solution would be to correct the specificity of the rule so that it always overrides whatever rules already apply.
This is not necessary, After some testing I have determined that your suggestion does not cause problems in most themes and I will include it in the next patch.
Thank you. Hope you have great holidays.