The needle is returning to the wrong position.
Check needle position buttons
Ensure that the needle position is set to be needle up and not needle down.
Check index counts
Ensure the index itself is working. This is done by turning the hand wheel by hand, and looking into the rear PCB box (easiest is through the robotics port, but if you can’t see the robotics port, any port will do), there is a red light that should turn on each time the machine needle gets to the up position. When you pass the up position, it should turn off. Confirm the light comes on and then off as you get to the up position.
In relation to this light, the EXACT “needle up position” is when the light goes from OFF to ON. Confirm as you turn the hand wheel, watching the light through the cover, turn it slowly and when the light goes ON. The needle should be in the up position. If it is not, the flag / magent is set to the wrong position and you will need to contact your dealer to get this reset.
Check if index counts are counting in Folder -> Diagonistics -> Motor Index button. Turn the handwheel by hand and see if index flag is updating. Make sure the belt is connected as the motor needs to turn as well.
If there are multiple Index Counts per revolution(Index Disc Only):
The index disk is probably oblong and is toggling the index in the wrong position.
If there are multiple index counts per motor-powered revolution (pressing the needle up button) and normal index counts when turned by hand:
Check the earth ground connection to the casting. If it is not connected it will give many index counts when the motor EMF interferes with the PCB.
Check Index
Ensure that the index is set correctly inside machine and the flag is being engaged in the index channel.
Ensure that the index flag is not spinning freely on shaft.
Ensure that the motor pulley is not spinning on the motor shaft.