It has been seen in the iCloud backup since iOS 8 from 10 years ago and most users just turn it off if there is not a need for Siri Suggestion on those keyboards. It can appear whether you have the keyboard added or not.
It is not anything nefarious, but you can still contact Apple directly if you wish. When it was first reported, users thought it was some kind of Malware, but it is not. There is nothing to worry about, but if you do contact Apple, please update with their response as it has been a couple of years since the last report here and an update may be helpful.
Contact Apple for support and service - Apple Support