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