I believe the issue is the method that is being used to manually insert the
connections_entry_id user meta in the DB (your code, I assume). I would examine how you are adding the entry ID value to the user meta.
In regards to where
self::$entryID is being set, it is in the
setEntryID() method. It is imply using
get_user_meta( get_current_user_id(), 'connections_entry_id', TRUE ); to get the meta value. The value must already have had the added characters added.