CIS always has the ultimate power to approve/deny one's I-140, and therefore it is not a surprise they revoke an approved I-140 if they have a good reason. This is also why people without a strong GC case should NOT go with WOM simply to minimize the risk.
Now for naturalization case itself, CIS actually loses the adjudication power once a litigation is filed in district court against them, especially for 9th Circuit Court regions. Google Hovsepian v. USA you will find out why -- In that precedence, CIS attempted to deny Hovsepian's N-400 while a lawsuit against CIS is pending based on the fact he was a terrorist before. However, the 9th Circuit Court ruled against CIS that they had no power to do that as Hovsepian sued CIS for prolonged delay of his N-400 adjudication and proceeded to approve his case in the court. That is also why many lawyers only take 1447(b) cases within the 9th Circuit Court regions as it is a slam dunk with this precedence.
Now for naturalization case itself, CIS actually loses the adjudication power once a litigation is filed in district court against them, especially for 9th Circuit Court regions. Google Hovsepian v. USA you will find out why -- In that precedence, CIS attempted to deny Hovsepian's N-400 while a lawsuit against CIS is pending based on the fact he was a terrorist before. However, the 9th Circuit Court ruled against CIS that they had no power to do that as Hovsepian sued CIS for prolonged delay of his N-400 adjudication and proceeded to approve his case in the court. That is also why many lawyers only take 1447(b) cases within the 9th Circuit Court regions as it is a slam dunk with this precedence.