Since you are doing the tests could you try it with these parameters?
Fight the goblins at the top floor of Selune's temple ruins. No hiding or cheesing.
Party consists of Wizard, Rogue, Warlock and Cleric. Cleric: Autoattack and Cantrips Wizard: Only Cantrips Warlock: Eldritch Blast (OT 36% hit rate when in front of the target?) Rogue: Sneak attacks, off hand strikes and auto-attack
This was the setting where I saw the phenomenon.
Do you have a save of that? I needed to do an altogether new save and level up first, and can you be more specific what you saw? Eldritch blast gets a disadvantage if the opponent is too close, for instance (e.g. standing right "in front of them"). However, the percentages displayed take this into account correctly.
The next time something like that happens it may be an idea to keep a (previous) save or some such, also for a possible bug report.
