For the record, fixing that then exposes an error in
example(geom_pointpath) "invalid line type", which appears to come from
NAs in the last row of 'df' within GeomPointPath$draw_panel(), which
appears to come from ...
df <- within(munched[munched$length > threshold,]
... because the last value in munched$length is NA. Unfortunately, this
is too deep for me to fix.
Paul Murrel wrote 24. feb. 2020