Lava lamp does not flow fully

Hello all, I’m a brand new owner of two lava lamps I received as Christmas gifts. They’re Schylling brand (the ones they sell at Spencer’s in the US) and they’re 16.3”. One is orange/purple, the other is black/clear.

I’ve been loving them, but there’s an issue with the orange one. While it does heat up, it does not seem to reach the flow levels that the black one does. It heats up slower, and once it is supposedly at full heat, it does not “dance” the same way the black one does. The wax will often rise into a “pillar” shape from top to bottom, and will break off very slowly instead of quickly tapering and breaking into the smaller wavy blobs you’d expect.

I’ve tried adjusting it with dimmers (even at 100% it behaves like this), and have even tried switching the bottles to see if the problem lies with the actual base/bulb, or the contents of the bottle. Both bases seem to affect the orange one the same way, and both work fine with the black one.

I should mention the orange one does have some small bubbles in the wax that are only noticeable up close. I’m not sure if the black one has them since the black wax is completely opaque.

One hypothesis I have is that the orange one has too much wax and therefore can only conduct the heat so fast, stifling its movement. Is that a possibility? I have no idea what else could make the orange one behave like this.

Any suggestions on what the problem is and how to address it is appreciated!