  Convective boundary mixing (CBM) is ubiquitous in stellar evolution. It is a
necessary ingredient in the models in order to match observational constraints
from clusters, binaries and single stars alike. We compute `effective
overshoot' measures that reflect the extent of mixing and which can differ
significantly from the input overshoot values set in the stellar evolution
codes. We use constraints from pressure modes to infer the CBM properties of
Kepler and CoRoT main-sequence and subgiant oscillators, as well as in two
radial velocity targets (Procyon A and $\alpha$ Cen A). Collectively these
targets allow us to identify how measurement precision, stellar spectral type,
and overshoot implementation impact the asteroseismic solution. With these new
measures we find that the `effective overshoot' for most stars is in line with
physical expectations and calibrations from binaries and clusters. However, two
F-stars in the CoRoT field (HD 49933 and HD 181906) still necessitate high
overshoot in the models. Due to short mode lifetimes, mode identification can
be difficult in these stars. We demonstrate that an incongruence between the
radial and non-radial modes drives the asteroseismic solution to extreme
structures with highly-efficient CBM as an inevitable outcome. Understanding
the cause of seemingly anomalous physics for such stars is vital for inferring
accurate stellar parameters from TESS data with comparable timeseries length.
