The L805 is about the latest printer model in a long series of photo printers with similar properties - 6 inks - good
overall printing quality. It started with a R265 and related combo-models, the R285, the P50 for quite some time, and
the XP-55 today all with cartridges and the Claria inks. The L800/805 are CISS type conversions which Epson does/did not offer in all European countries, but years earlier already in other regions - e.g. South East area - Singapore etc .
I got mine via Poland as a gray import. I was running it for quite a while - probably 2000 A4 photos with pigment inks - and then switched to dye inks - all without a problem - printhead or else. It is now replaced by an L1800.
As
@websnail is pointing out Epson is very reluctant to release any reasonable information about the performance of their inks beyond marketing speech - prints will last for generations to come (in an album in a cabinet) but not much more. Plenty of tests had been done by Wilhelm Research WRI and Aardenburg showing wide performance differences,
just forget the 664 inks for the L300, ET-2600 etc in regards to fading stability, they are no better than cheap refill inks, inks for the L800 are somewhat better in this respect but not Claria like. Epson is offering a printer model ET-7700/7750 as well with tanks, with the 106 inks. A test in a German computer magazine c't showed that this ink was performing as good as the Claria inks in the same test, yes - Epson can do it, but won't tell you. I did some follow up tests and can confirm that, the 106 inks are the best Claria like inks like you can get - in 70ml bottles. I cannot say it is the same ink but an ink with a comparable fading performance vs. the Claria inks. And Epson has another similar ink in their range, not in the consumer market, the Epson Surelab printers like the D3000 for commercial photo printing services are using an 'Ultrachrome D6' ink set (dye 6 oclors) in larger cartridges - up to 700 ml, and these inks perform as well very similar to the Claria inks - so yes - Epson can do it but won't tell you. You can drain such cartridges easily.
But let's get back to your issues - differences in the printout - as discussed above it could be a profiling issue, driver settings or a contrast issue between the matte pigment inks and the dye inks - or something else