I have conducted a Sweatbox session and the student assigned four different squawk codes which I can find now as used in the reserved codes list.
The data below is taken from the reserved codes list.
1454 2023-08-24 17:15:50
4066 2023-08-24 17:31:26
1215 2023-08-24 17:32:17
7710 2023-08-24 17:39:28
All these squawk codes were assigned on Sweatbox, but they are also reserved for VATSIM servers.
Previously, we had a similar situation, in the Sweatbox session there were assigned squawk codes in range 1701-1711, and online, the first code available was 1712.