I have been building an app that makes extensive use of sockets throughout the beta period and now with the release version and have not had any problems with that. I haven’t released anything compiled with 2019r1 yet, but am just doing a final build for testing now and will let you know if I have any problems. I am aware that they made changes to the new URLConnection class, but I don’t know if there were any changes to anything lower level than that.
The best thing you can do is to zip up the project and open a private feedback report to Xojo. If they can duplicate it then they can fix it, if you can’t collect any other info about where it’s happening then this is the best option. Otherwise they won’t even know where to start.