Telescope failed to perform meridian flip

I've checked the driver log and code in detail, this is the relevant section, with annotations to explain what is going on

SGP checks if the pier side can be set
00:58:58.430 CanSetPierSide True

SGP send the message to change the pier side
00:58:58.430 SetSideOfPier set to pierEast

checks if this is possible
00:58:58.430 SideOfPier throttled pierWest
00:58:58.430 SendMessageTerminated send c0001
00:58:58.447 SendMessageTerminated received 00000001#
00:58:58.447 MeridianMode get favourWest
00:58:58.447 MeridianMode set favourWest
00:58:58.448 SendMessageTerminated send C0001,00000001
00:58:58.470 SendMessageTerminated received #
00:58:58.470 SendMessageTerminated send g1258DD00,24BEDE00
00:58:58.499 SendMessageTerminated received W#
00:58:58.499 DestinationSideOfPier from hw, Ra 1.72004270553589, Dec 51.6734647750854 = pierEast
checks completed, the specified pointing state can be reached

00:58:58.499 SetSideOfPier Slew to pierEast
async slew command sent
00:58:58.499 IsGuiding isGuiding (False || False) = False *** part of the slewAsync method
00:58:58.499 SendMessageTerminated send r1258DD00,24BEDE00

00:58:58.512 IsGuiding isGuiding (False || False) = False *** not sure, could be from SGP

00:58:58.566 SendMessageTerminated received #
slew started, checks of the pointing state, slewing state and position will check the hardware

SGP asking for the tracking state, before SetSideOfPier has returned
00:58:58.566 SendMessageTerminated send t *** read tracking state command

00:58:58.566 SlewAsync Ra 1.72004270553589, Dec 51.6734647750854 *** part of SetSideOfPier

SetSideOfPier returns here.

00:58:58.570 SendMessageTerminated received [02]# *** reply to 't' command
00:58:58.570 Tracking get Tracking True, mode eqN

SGP asking for the pointing state
00:58:58.616 SideOfPier throttled pierWest
00:58:58.672 SideOfPier throttled pierWest
00:58:58.933 IsGuiding isGuiding (False || False) = False

SGP asking for the position
00:58:58.933 SendMessageTerminated send e
00:58:59.001 SendMessageTerminated received 12976F00,24FD5500#
00:58:59.001 GetRaDec Ra 1.74295663833618, Dec 52.0165944099426

SGP asking for the sidereal time
00:58:59.048 SendMessageTerminated send l
00:58:59.104 SendMessageTerminated received 1337C200#
00:58:59.105 Sidereal time From mount 1.80166912078857

SGP asking for the pointing state, before checking the slewing state
00:58:59.106 SideOfPier throttled pierWest
00:58:59.173 SideOfPier throttled pierWest

SGP asking for the sidereal time
00:58:59.318 SendMessageTerminated send l
00:58:59.375 SendMessageTerminated received 1337F600#
00:58:59.375 Sidereal time From mount 1.80174350738525

SGP asks for the slewing state for the first time after set sideOfPier returns
00:58:59.376 IsGuiding isGuiding (False || False) = False
00:58:59.376 SendMessageTerminated send L
00:58:59.380 SendMessageTerminated received 1#
00:58:59.380 Slewing state True
Slewing state returned as true

The driver is checking that the new pointing state can be reached and sends a async slew command to start the slew to that position.
This has completed sucessfully before the time of the error reported in the SGP log.

There are then several reads of the pointing state BUT no check on the slewing state until after that. The first check on the slewing state reports that slewing is in progress.

It looks as if SGP is reading the pointing state before it checks the slew state.

Chris