If the interview resumed normally and the interviewer was aware of the connection issue, you usually do not need to turn it into a major incident. A short note can be appropriate if the disruption materially affected the interview.

Technical issues happen in virtual interviews. What matters is whether the interviewer could complete the assessment fairly. Repeatedly apologizing for a brief interruption can create more attention than the problem itself.

If you lost 90 seconds but rejoined and finished the full case, a normal thank-you note may be enough. If you missed a question, lost significant time, or the interview ended early, contact recruiting and explain exactly what happened.

Write down the duration and impact of the disruption. If it affected the substance or timing of the interview, notify recruiting promptly and factually. Otherwise, send your normal follow-up and move on.

If you finished normally I probably wouldn't make a huge deal out of 90 seconds.

If it cost you actual case time, then yes I'd tell recruiting.