Apologies if this sounds snotty, but there's actually no such thing as an industry standard for Ethernet cables.
The provided cable is a more modern design and are commonly available.
There are a few types of cables that have a hard plastic moulding that extends outside of the clear plastic connector and these types of cables can't be used.
It's also more difficult using cables that has a dust shroud, but I'm using one on my Almond+ at home without any issues at all.
It would be good if you guys could share pictures of the cables you're having problems with.
In as much as this is an issue and we're not trying to say that we didn't make a misjudgment as to how big of a deal this would be, it shouldn't be very hard to find suitable cables.
We'll post some pictures later of the various types that we've tested that works and the few that we've had problems with.