There were other all J from Privatair on behalf of Swiss, Lufthansa, KLM...
DUS-EWR, ZRH-EWR, AMS-IAH, MUC-EWR, DUS-ORD at various times in the 2000s
https://www.ft.com/content/e039d10c-...e-00000e2511c8
They went insolvent in 2018 but did survive the 2008 crisis - did more Europe-Africa/South Asia ops after that. Might be less of an indictment of small scale all biz class operations than the carriers that contracted them finding demand suitable for normal service
Fascinating rumor but it might apply to just one or two airframes if it has any truth to it at all