That's very odd.
1 First thought is a shade tree mechanic did it to improve the fit (similar to peening in the old days). But no, the lines are too straight/perpendicular to have been done by handtools.
2 Second thought - somehow (lord only knows how) the lines formed at the location of the rolling elements. But no, I sincerely doubt this scenario. I'll ask anyway: are these cylindrical roller bearings? Does the line spacing resemble the roller spacing?
3 Third thought. Some or all of the marks occurred assembly (or previous disassembly / assembly in case of the housing). Possibly some abrasive debris was trapped between the two. (how did both surfaces get damaged: 3A some particles stuck on bearing and damaged housing while other particles stuck on housing and damaged bearing; 3B a given particle may have slid along one surface until it caught/stopped, causing damage to the other). I notice at least 3/4 lines go all the way to bottom of photo but not to the top... I assume top side of bearing faces shaft shoulder? I'll bet the housing bore lines extend only over part of the axial distance also.
It seems to me the most plausible of above scenario's is the third. Photos of housing damage might give fodder for further speculation.
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(2B)+(2B)' ?