So to keep this post updated and let everyone know that this is an official bug! I never got around to testing it out myself to find out but I guess someone did! And therefore the issue has been presented here:- https://www.reddit.com/r/operabrowser/wiki/opera/known_issues/#wiki_deleting_history_entries_can_wipe_out_all_history_when_opera_sync_is_enabled
@burnout426 Informs me that the bug hasn't been solved yet.
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