CAN disconnecting when Input Shaping frequency is below 12Hz

[droftarts]

Latest thread: https://forum.duet3d.com/topic/38135/3-6-0-expansion-board-disconnecting
Initial thread: https://forum.duet3d.com/topic/37797/3-6-0-rc-2-code-3-move-error/

User reports Y-Axis EXP1XD board is disconnecting when printing a succession of short segments (text) if the input shaping frequency is below 12Hz, in with RRF 3.6.0.