I have upgraded from the AX 100 to the 700. Awesome camcorder BUT whilst it will record XAVC S 4K on the 128 Gig SD card it stops recording just before the 60 gig point. Am using Sandisk Extreme Pro Class 3 128 gig cards. The manual says I should get approx 150 minutes on this card. Am recording in Pal. 2160/25p 100Mbps. Does anyone have any suggestions?

Counterfeit card maybe?

+1 for Nate
Counterfeit card maybe?
There's a lot of counterfeit stuff out there ... and the counterfeiters are getting better [Edit: as in harder to detect].

It almost seems that when reviews about counterfeit stuff is posted on web sites (say, YouTube) then the counterfeiter tweaks their junk to make it better so it is harder to detect.

Nate - after reading your post, just for the heck of it, I did some searching and found a few good sites. On of them on YouTube, very long, was titled "Ebay & Amazon China SD memory card scam & how to protect yourself" and this guy used a program "H2testw". Watch at ~ 8:00, ~9:50, and again at 21:35

Unfortunately, the poster said that trying to find H2testw to download was really difficult because so many of the downloads included viruses. Question: What are the chances that same people making the counterfeit items would search out the program then hack the server to include the viruses?

Adding insult to injury, some of the counterfeiters put "Made in Taiwan" instead of Made in China on the item. Could this be economic warfare?

Disclaimer: Not sayin' the card WAS counterfeit, but just agreeing that it MAY be counterfeit. However, given the track record of these items I would have my suspicions. There always is the probability that a manufactured item can have a defect.