This behavior indicates an SD card read/write issue or it can be a connection issue with the SD card socket.
Please remove the SD Card and reformat it. Make sure it is Formatted to FAT32 or insert a new SD card in the sign and re-send the schedule again. See FAQ, How to Format a SD Card.
It may also be your region is not set correctly for the State or territory your trailer is operating in. see below sample is set to VICTORIA TIME ZONE
Contact the Help Desk if this is not correct for your state or territory.
The other issue may be, the GPS signal is not being received.
On earlier models you need ensure you are running correct firmware version as there was a GPS update required after April 2019
Model firmware should be as a minimum as at May 2019 for the controller models show below;
RM-32 06.03.11 Note this controller is Legacy and may need replacing if continued unreliable operation persists.
If this does not fix the problem then please contact the Service Desk to arrange for Service to your Sign