This looks fine to me, here's the reason I'm saying that:
When you install a EDM 7xx you install six new EGT and CHT probes in the exhaust pipes and cylinder heads respectively. The CHT probes are installed in a pre-drilled hole located on the bottom of the cylinder head aprox. three inches inboard from the spark plug hole. The #1 mounting location however is already taken up by Cessna's OEM CHT probe, so a different type of probe called a "Ring Probe" is supplied with the installation kit to be installed underneath one of the spark plugs in that cylinder. This produces a "different" heat value for that cylinder due to the heat dissipation pattern of the cylinder head. (note that JPI states that "the gasket probe may read 25 degrees F. higher or lower than the factory probe", although I have seen bigger differences)
The OEM probe is installed in the #1 cylinder to begin with because it is usually the hottest running cylinder due to being in the aft r/h location, lots of heat can build up back there, as noted by the EGT reading. The recorded temps for #1 CHT & EGT are also corresponding at the same rate of change as the rest of the cylinders, no extra jumps of jitters, sure signs of sticking/bent valves.
Also, as a last opinion, a decrease of a full 1/3 of your CHT temp, if indication of a lack of compression and combustion would surely translate to a abnormal difference in EGT, which is not present.
All that being said, look at your EDM historical downloads if you have access, is this a normal reading for this engine? Is the aircraft fresh from a 100hr or annual where the CHT probe may have been damaged or installed incorrectly? And really, it's never a bad idea to crack the cowling and take a look at it, a quick compression check would put any doubts to rest.
Definitely discuss this with your local mx guy though, better safe than missing a cylinder at 10k feet
CC