While running precheck two checks failed. At the end, it shows only one failed. Is it a bug?

I think the magic drc checks are non-fatal. https://skywater-pdk.slack.com/archives/C016YSAP6TZ/p1654867379241259

Thanks for the explanation @Tim Edwards

@Lab Lecture; DRC checks in magic are "strongly advisory". You should avoid having DRC errors in your design. That said, however, there are some rules that we know are over-conservative and probably related to the original usage of the process by Cypress for memory chips, and can be ignored. However, you should make sure you understand the errors that magic is generating and that they are errors which you are willingly violating, and that you know why you are violating them.