JVC D-series odd issue with Groovymame /switchres

[benyamin39]

I have a groovymame arcade cabinet (Lenovo M58, windows 7 crt, ATI HD6450, crt_emudriver_&_tools_2.0_beta_15_16.2.1_W.7.8.10-64_NonGCN, attractmode front end), hooked up to 3 RGB modded CRT TVs : a Samsung, a Sony and a JVC D-series via a powered VGA splitter. I am pretty knowledgeable with the subject (I built the cabinet, modded the TV sets, installed and configured the groovymame myself)

I have a very odd issue with the JVC TV, when using groovymame and the some of the arcade cores such as final fight and Asterix. I believe the issue is either in switchres or some settings on the TV (hidden deep inside the service menu)

I do not have issue when running games using bsnes emulator / MisterFPGA / MAME Genesis on all monitors. So I believe the problem is not in the hardware (splitter or cabling and even Computer itself, or emuCRT, or the roms)

I have issue when playing groovymame arcade games Final Fight or Asterix (and probably others), the image is very degraded, dark with parasite lines all over the screen. It is unplayable. The colors are particularly wrong on the Asterix game. I do not have issue with the Samsung or the Trinitron. Playing games such as Altered beast is fine though.

I connected my JVC directly to the cabinet without the splitter, the problem remains.

Attached are the pictures. This is a very odd problem. The JVC set is sensitive to the VGA signal sent by Groovymame when running those games. Could it be related to switchres? Note that I do not use superesolution.

I could not find a post with similar subject. Anyone can point at a direction where to look at?