Been using Squirt for the last 4-5 yrs now and will continue with wax-based bottle lube in the future. It’s so much cleaner than oil-based lube. But I learned the hard way the first time about chain prep. Mixing the old lube with Squirt is fine lubrication-wise. It just turns into a huge mess. To properly prep the chain, it needs to be off bike. Also, it’s best to start with a new chain. Place it into a container with a good amount of degreaser (I used full concentration Simple Green). Wait and hr or so. Use a brushed to agitate the chain rollers. Repeat. And then rinse with water and then make sure chain is absolutely dry before liberally applying Squirt to the top and bottom of the chain. Wait for it to dry completely (a hair dryer can speed this up). Repeat another coat of Squirt.
I think you went wrong was that you applied Squirt with some water in the rollers and this may have caused some corrosion in the pin/roller.