MacBook Pro 2018 Mojave 10.14.3 Radeon Pro Vega 20 4080 MB Intel UHD Graphics 630 1536 MB Connected via the provided USB-C to C cable I've tried a hard reset and a factory reset
When my MacBook Pro goes to sleep, the U3419W scans for a signal about every 15 seconds. My issue sounds very similar to this post however the computer end of things is a Mac and not a PC so it's not much help.
Re: U3419W, scanning for signal when Apple is asleep
For my Dell internal notes, click my name and private message me the U3419W service tag number.
Is there a Windows operating system PC to test the U3419W on? We did not provide any Apple operating system drivers. We only provided an Apple operating system firmware updater file. You should also post the issue on the Apple Forum and see what other Apple users have done as far as Apple PC troubleshooting.
Testing = Open the U3419W Menu. Go to Input Source. Check/Select USB Type-C. Change Auto Select to Off. Retest