https://motherboard.vice.com/en_us/article/negayg/texas-voting-machines-have-been-a-known-problem-for-a-decade

Texas voters experiencing issues with voting machines used in that state have been told by election officials that they are the problem, not the machines. The state says voters are inadvertently touching the machines in ways they shouldn't, causing the machines to alter or delete their vote in the hotly contested senate race between Republican incumbent Ted Cruz and Democratic challenger Beto O’Rourke.

But Dan Wallach, a computer science professor at Rice University in Houston who has examined the systems extensively in the past, told Motherboard in a phone interview that the problem is a common type of software bug that the maker of the equipment could have fixed a decade ago and didn’t, despite previous voter complaints. What's more, he says the same systems have much more serious security problems that the manufacturer has failed to fix that make them susceptible to hacking.