OK It should work with Fastest route + jet cone boost selected, and the route recalculated (I'm a very experienced Fuel Rat and deal with this all the time). The info below is reasonably accurate, and proven across multiple installations.
Current Galmap routing bugs (As of Odyssey U14):
1) Routing mode is not set after game login. Post U14, the UI setting is restored, but the setting is not set properly behind the scenes.
Background: My observation (this bit is representative but is not 100% proven or might vary across systems) is that in this uninitialised state, galmap plots as Fastest route, with jetcone boost, NO filters, and ZERO cargo. (meaning if you have cargo, it can plot over-length jumps)
Workaround: After game login, toggle "Fastest route" to "Economical route", and back to "Fastest route". Select "Use Jetcone boost" if you wish (you need it for your issue above0.
2) "Apply Filter to route" can go missing from filters, or filters can become corrupted between logins.
Background: The setting can go AWOL on its own or if you click around filters, and a casual glance at the Star Class filter will appear in order, you need to scroll down to see that "Apply filter to route" is gone :/
Workaround: If using a filter based on star class (or other filter that has "Apply filter to route" selected). Check that setting is still there after logon (or if the filter appears to fail).
3) If you end up in a Neutron system or White Dwarf system, Galmap will not plot an unboosted jump out.
Workaround: If you choose not to supercharge your FSD and the plotted jump segment is over your jump range, you will need to target an adjacent star manually, jump out, then let your route re-plot.
4) In some cases the recalculate button might not not enable, or if enabled, function correctly.
Workaround: If you suspect an issue, clear your route then replot from scratch.
A bit of a palaver, but follow those workarounds, Galmap should work enough to get around.
Ho Hummmmmm....