What happens if it's discovered that either one party lied to the court about serving the other party or the server (a friend) lied about serving the papers, so, in effect, the person lied about serving the other party in a custody case?
Courts generally do not like complaining about service issues. If you know about it and can respond, focus on the merits of your case not the service issues. If you have been hurt by the lie then of course bring it up to the court.
If the court finds the server lied, he could be charged with perjury by the DA's office, or if a registered process server, could have license issues. If a party is damaged by the lie, he could sue for the damages. If the party lied, and not the server, the court could sanction the party. Obviously it will affect the credibility that party has as the case goes forward. However, in practice, judges do not generally want to get into a hearing on such issues, unless they are particularly relevant to the issues before the court, such as a party has a default judgment against them and later files a motion to vacate, claiming no service.
The other party will make a motion to quash the service of the petition. Unless they consent to being served, the case will be deemed as though the party was never served. Never falsify information to the court. It affects your future credibility in the case.
It is unclear from the limited facts whether you are the affected party or not. For improper service issues, the affected party can file a motion to quash service and attach all of the evidence of the improper/ineffective service. Depending on the status of the case (was a default entered, does an answer need to be filed), the judge can then make orders accordingly. Criminal charges can also be sought for perjury, although the DA may or may not pursue it. Hope this helps. Good luck.