According to this NASA Document the lift after the propeller is higher and it is used on purpose to create more lift.
Wing-mounted propulsion systems have significant effects on the wing
aerodynamic characteristics, and these effects are more pronounced
when the highlift components are deployed. Various aerodynamic
components contribute to the rise of these effects. Some of these
effects are external to the wing performance and affect the
measurement of the aerodynamic characteristics of the combined
assembly. Examples of these effects are the propeller thrust, the
location of the thrust line, tile size and location of the exhaust
nozzle, and the thrust from the exhaust nozzle alone. Another group of
effects are pure aerodynamic effects, such as the propeller
slipstream and the flow past the nacelle and nacelle attachments.
Results indicate that the lift coefficient of the powered wing could
be increased by the propeller slipstream when the rotational speed
(disk loading) was increased and high-lift devices were incorporated.
It is also stated, that the exhaust of the turboprop can also create lift.
An exhaust of a free-turbine "PT6A-67" turboprop of a converted Conair Firecat doesn't generate any lift.
But an exhaust of an Direct-drive "Rolls-Royce RB.53 Dart" turboprop YS-11 which is nearly on the wing, can generate additional lift and acceleration.