Hi Mark!
Thanks so much for taking your time to report this.
This is indeed a warning that pops up when using PHP version 7.2, which is the latest. We are aware of some adjustments that we need to make in the code to prevent these type of warnings.
It does not necessarily mean something is not working (if it does affect functionality please let us know) but is definitely something that we should address, so I have created a report for this issue and link it to this thread.
I have set this thread’s status to “Pending fix”, so we will notify you once a fix is released in one of our next maintenance releases of our plugins.
We will keep you posted about it.
Best,
Victor