NOS Mullard EL34 indicates overload during testing

Had some vintage Mullard and Telefunken EL34s along with some Sylvania 6SN7s tested yesterday. They were tested on a Triplett 3444 by a trusted gentleman who specializes in tube gear and has been operating a brick and mortar HiFi retail shop in the same location for over 40 years. I've had several dealings with this gentleman and his reputation is beyond reproach. The Sylvania 6SN7s were purchased from a while back and tested well. The Telefunken EL34s came with a recent purchase of a Linear Tube Audio ZOTL40 while the two pairs of Mullard EL34s, one pair labeled Amperex and a second pair came in Mullard boxes, were recent online purchase from USAM.  Most tubes appear to be genuine and tested as they should, except for the pair of Mullard EL34s. Weak tubes test around 1700 and stronger ones around 2600-2700 on his Triplett 3444. The Mullards tested above 8500 and caused the red overload indicator to light up. He told me it could be nothing but be careful just in case as the tubes appeared to be genuine but the overload during testing gave him pause. He said I should be able to use it but be ready to switch them out just in case. I would rather not gamble on frying my gear with tubes that may or may not be suspect. Does anyone having technical knowledge of tube circuitry please chime in and explain the risk? Is this just an anomaly with the testing equipment or do some tubes really exceed the upper limits of what's acceptable for NOS tubes? Appreciate your opinion on the matter as I have little with regard to tubes or circuitry and am simply an enthusiast. Best, John
The world of NOS tubes is interesting, indeed. Please note that "NOS" means "New, Old Stock." Unfortunately, it is common to see so-called "NOS" tubes that are very clearly old, but not new. Of course, I don’t know whether that was the case in your instance.
... two pairs of Mullard EL34s, one pair labeled Amperex and a second pair came in Mullard boxes ...
That sounds odd.
My bad for the typo:  tests on the Mullard EL34s were not 8500 but rather 3500. Regardless, overload light came on. Thanks.
There is a physical defect in the valve. I wouldn't use it. I'll bet the wire is to thick. Simple explanation ay. The problem is the SQ of the valve will reflect that THICK (er) wire.  The older it gets the better it will read, but it will NEVER be a great sounding valve.  The last test of a valve is to listen to it, believe it or not.. How many do that?. Warm it up and listen.. LOL The only reason I couldn't make living at it.. TO DARN PICKY..

Here's the response received upon inquiry:

"Not every valve tester is perfectly accurate in every circumstance. I could ask my engineer to explain, but this will involve you me and him reading/writing long paragraphs. Our AVO VCM163 is the best tube tester in Europe. It may well be these EL34 have 10% more anode current than book value. This is still perfectly acceptable as NOS. Usually the “auto bias” on the amplifier will take care of this issue. But not every amplifier has auto bias. It will usually be ok but not in every case. This extra 10% may explain why your friend with the triplett tester said they were overloading.
These EL34 were tested before dispatch and should be should be perfectly usable. To summarise I think the tubes are perfectly safe to use."