It's weird but there has been a few posts recently where people have pulled apart 3-way switches and put them back together wrong. And they've had similar behaviours that you have. I guess more people are trying to do DIY electrical due to covid.

I'm assuming you don't have pictures of the 'before' situation?

Do you at least still have the old switches? Sometimes the location of the screws can be different but the colour of the screws should distinguish between the common screw and the travellers.

Can you describe the 'after' situation and show pictures of all the wires in the box and how they are attached to the switch?

Do you have any type of voltage testing tool?

Thanks for the response; unfortunately I threw the old switches away. They looked super old and had no distinguishing color for the traveler and common wires.

The strange thing is that they were originally installed upside down; so i installed the new switches the same way (upside down) so I could match the way the wires were attached to the new fixture.

3-way switches don't have a particular direction that they need to be installed. It isn't like up is 'on' and down is 'off', like with regular switches.

If you can answer the second two questions of my first post, we can start trouble-shooting this and figure out the correct way to wire it up. Randomly hooking up wires is not a good way to do electrical work, so it's a matter of figuring out how it should be wired up before doing anything.

I'll take a picture and respond to your thread. I used to have this

https://www.homedepot.com/p/Klein-Tools-Non-Contact-Voltage-Tester-NCVT-1SEN/100661787

But i'll need to buy another one. The battery leaked all over the inside.

While the non-contact testers are a safe way to see if there's power, they can also give you false positives. ie. Tell you there's power when there really isn't. Google 'phantom voltage' for more info.

This is a good tool to actually test with:

Voltage Tester

But you have to actually touch two bare metal points to test the voltage. Usually the wire that you are testing and a known good ground.

I have some older 3 way switches in my house (maybe vintage 1940) and have had to make adjustments when replacing them with modern 3 way switches. The terminals are not in the same locations on the switch body, so when I tried to use the old switches as a template I ended up with switches that did not work right. I had to work through each one and look carefully at the markings to determine the right terminals.

Bruce

You have to be able to identify the wires and you have to read the instructions. You can't go by installing it based on the way the old one looked to be installed. I once needed to replace a 5-year-old 3-way switch and bought a replacement that was by the same manufacturer, had the same appearance, and had the same part number...so I didn't bother looking at the instructions. After installing it, it wasn't functioning properly. After checking the connections to make sure they were tight, I finally got around to reading the instructions. It turns out that the internals had been redesigned and two terminals had been switched in this seemingly identical switch. Once I read the instructions I got it hooked up correctly.