I updated my 4235 today with 3.1(4)S53 and S54 through VMS. I didn't watch VMS closely between updates so I'm not sure which update did it; I just verified on the sensor that S53 was installed and then pushed out S54. In VMS that sensor lost its signature list. Under General I showed 0 of 0 signatures. It still showed custom and the rest but the General was empty.
I looked there to turn off the Nachi signature that had just come out as the sensor sits outside the firewall and was recording about 1,000 signatures a minute. I manually turned off the signature in packetd.conf to stop the spam. I then deleted the sensor from VMS and re-imported it successfully.
This is the only 3.1(4) sensor I have. The others are blades and 4.1(1). I'm not sure what caused this but I thought I would post to get feedback to see if this happened to anyone else.
Thanks.