The Shapeoko 5 Pro does not have sensors or any sort of feedback on positioning.
Because of that, one has to be conservative about cuts and toolpaths and tooling engagement.
As was explained in your support ticket, trying to cut a slot 0.94" deep w/ a tool which has only 0.75" of cutting flute length, which is almost 4 times deeper than the diameter of the tool is presenting the machine with a cut which might work at first with a new and sharp tool, but there is a likelihood that it won’t be completed successfully which only increases as the tool wears, or one tempts fate multiple times.
Where possible avoid slotting and add geometry and cut as a pocket
and/or
and consider leaving a roughing clearance and taking a finishing pass.