Hey Eugene,
there can be a lot of reasons. You did not tell which of the axes had their coordinates changed.
I would check all the points in this support document, one by one:
Also have you checked and ensured that your machine is
If rectangularity and coplanarity are not perfect, the Y movement can block or have “hiccups” or loose its position reference coordinates.
You did not tell whether you use a router or a spindle on a VFD. Both can cause electromagnetic interference (EMI), the first by its sparks from the carbon-brush commutator, the latter if the VFD is not enclosed into a grounded control cabinet or the spindle cable is not correctly shielded, grounded, and terminated.
Unfortunately, the stepper motor cables of the Onefinity machines are not shielded so they are susceptible for EMI.
Also you did not tell how long you already use the machine and which Series do you have (Elite Series, PRO/X-50 Series, Original Series), whether with drag chains or without drag chains). On older models without drag chains the lacking strain relief of the moving cables can cause connector problems, also the curly Z cable is not made for permanent motion so after one year of use sometimes you can have internal cable breaks that lead to steps lost and unattended loss of position coordinates.
Sometimes the buildup of static electricity (e.g. because of dust collection) can also lead to lost steps. To not only prevent EMI but also to comply EN/IEC 60204-1 safety standard, the machine has to be electrically bonded and grounded. Here the links with the relevant information on how to do this: