TP4056 battery output (charging voltage) is not constant
The TP4065 could be detecting there is no battery, or a battery that is out-of-spec for normal charging, and do as it sees fit.
It could also be going into CC-charging mode, and then it's a current source and not regulating voltage. Its behaviour in the absence of a battery may well be described in its datasheet, I haven't checked.
Anyway: it will be hard to test properly without a battery connected. Pros use a Battery Simulator; when in doubt, I just take the whole rig outside, use a battery, and stand well back; not as safe, but much cheaper.