Fatal error at event: End Of Path

[AlexKhayrullin]

In Tidal Tubes 1, after going very fast for some time, I got this error and the game closed:

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FATAL ERROR in
action number 1
of Other Event: End Of Path
for object objPlayer:

DoSub :2: undefined value
 at gml_Object_objPlayer_EndOfPathEvent_1 (line 7) -     var path_yspeed = ds_list_find_value(ytable, offset)-ds_list_find_value(ytable, offset-1);
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stack frame is
gml_Object_objPlayer_EndOfPathEvent_1 (line 7)

This seems to be a rare occurrence.