Getting a crash with adding custom palette guitar finger slide symbol.

Hello,
I've attached Lagrima score and my custom 'guitar extras' custom palette.
Look at the score - first measure will do - first slide first finger up to the 'a'. To get the slide symbol in the correct position i need to select the left hand finger '4', then uncheck automatic placement in the inspector, then select the note itself, add the up slide symbol, and move to the left and down a bit - all good. But if I forget to select the note and leave the '4' selected and then add the slide symbol from the pallette then crashes i.e trying to add the slide symbol (by mistake) to the '4' instead of the note. (The slide symbol I use was taken from the master pallette somewhere but I can't remember where.)
Anyway, could someone have a look.
(Using Musescore 3.05 revision 3543170 on Linux.)