virus testing - false positive?

[Jmoney]

I wanted to ask people here if they have heard of any false positives with virus testing. (I did a search but didn't find anything on this). Let me expand a bit:

I recently bought a fairly expensive phalaenopsis stem prop from a well-known vendor in the US. The plant originally came from Taiwan.

I don't grow a lot of phals, but I do like to collect heirloom cattleyas, at least the ones that I can afford, and try to keep my modest collection virus-free. I use the Agdia ImmunoStrips which seem quite popular.

Anyway I test this new phalaenopsis and it comes out positive for ORSV and CymMV. pic attached. I email the vendor (without any accusatory language, mind you), and was basically told it was a false positive, and that there's a ton of information about how unreliable these virus tests are, etc.

Now as far as I've seen, and granted I'm not a microbiologist specializing in orchid viruses (and as far as I know this vendor is not either), people in the cattleya community seem to regard Agdia as a reliable test, and often use it to advertise their verified virus-free plants. A search did reveal possible issues with a batch of Agdia tests from 2012 causing false positives, but that's like ancient history as far as I'm concerned.

Basically I'm not buying the story that this is a false positive, and think it's much more likely that this plant is somehow truly positive, and I'm not too pleased that I was not offered a return on this plant. But I want to perform my due diligence and see if anyone else might think this is not a true test result.