@gtphoenix yes it does negates the efficiency of the plugin.
I’m sorry but i should ask a few stupid questions:
0. Did you hit “Save changes” button when you disable the setting?
1. A you sure that exactly this cookie (apbct_timestamp) breaks the cache?
2. Does the cache plugin generate the report about broken cache instantly? Maybe there is some way to clear cache for this cache plugin?
3. Does the SiteGround using DataBase caching? It could save setting, still send the old data from database, even if you’re tried the other setting and it worked.
Anyway, please, install this version. I’ve disable the native cookie for apbct_timestamp, so it shouldn’t break the cache now. Let us know if the different cookie breaks it.
https://github.com/CleanTalk/wordpress-antispam/releases/download/Special/cleantalk-spam-protect.zip
Please, contact us.