While there is no single industry-standard term "SheetCam hot crack," this likely refers to a combination of SheetCam software configuration and the metallurgical phenomenon of hot cracking

Cracks may not appear immediately; they can develop anywhere from 48 hours to several weeks after the cut. CUMIC Steel Managing Cut Quality with SheetCam You can use SheetCam TNG

Remember: the goal is to get in, cut the metal, and get out before the heat has a chance to ruin the molecular integrity of your edge.

He re-posted. Ran the cut on a scrap piece.

When a plasma torch stops at the end of a path, the sudden loss of arc pressure and heat can cause the molten metal pool to collapse inward. This often leaves: A "Crater": A divot at the end of the cut.

Cracks often start at the entry or exit point of a cut because that is where the heat dwells the longest.

Additional Resources

Case Study: Solving a Sheetcam Hot Crack in 1" AR500

A user on the CNCZone forums reported that every 1" AR500 wear plate he cut cracked exactly 2" from the lead-in. He blamed SheetCam.

Essentially, your toolpath is "cracking" the integrity of the part because the physics of the cut weren't accounted for in the CAM software.