Mine wasn't conference call, but a similar faux pas....
As I was training my replacement prior to leaving Germany (US Army), we were called in on the 4th of July to prepare a report for the captain, for presentation to his commanders on July 6th. That year, the 4th fell on a Saturday -- we were a little irate, we could have done it on the 3rd with no issues. Mobilize in response to aggression? No problem, I'll do that at 2AM. Shuffle paper when I could be eating BBQ? Please.
Our task was to break down the entire company roster -- 160 at the time -- by job code vs. actual position filled.
In preparing this report, we made notes -- which were censored for the final draft -- which included some pretty opinionated comments about some soldiers. I threw the rough notes away (turns out, should have burned them).
While the captain was two hours away giving this report, I was being harangued by nearly every 'victim' on that draft -- the notes had been placed on a co-worker's desk, who was one such.
Wound up drafting my own write-up for that one.
I still laugh about it now, and this was 1988.