Please see this post by @Araminta:
To summarise, if the “Require ACF API REST” setting is enabled in Cwicly settings, you will need to also enable the “Show in REST API” setting for the field groups for the custom posts. Alternatively you can turn both of those settings off and this should also work.
If this doesn’t resolve the issue and refreshing the html and classes from Cwicly settings also doesn’t fix it, then more information about exactly how you have the archive page / query and filters set up will be required.
The only other time I have seen something similar to what is happening on your site is when there was an issue with one of our filters. Fixing the filter resolved the issue in that case.