How often have you been watering?

Once a week

Try watering less often, like maybe once every 2 weeks. I'd remove the damaged leaves.

Remove the old, blemished leaves as they become breeding grounds for mold/mildew and other germs. The one leaf is yellowing so it is past its prime. The other two are blemished from some kind of pathogens/injury and will only get worse (and weigh on your nerves too as they get worse).

Sometimes it is hard to remove leaves due to the old myths that the plant needs them to photosynthesize which is true but the plant should have enough reserves in its roots and stems to regenerate new leaves. I often remove every damaged leaf off some plants (outdoor plants and houseplants). New leaves often appear within a couple of weeks. Sometimes I have to cut the entire plant down due to death in the stems for whatever reason and the plant will often send up new shoots from its roots.

Thank you!

I am encouraging mine to get bigger leaves by tying the two longest vines to an oak tree. It ran up my beech tree two years ago because I put the pot so close to this tree. The leaves probably doubled in size that summer.

2018 growing up a beech tree

This year.

Pls search around here for "using a tell" to learn when to water.

You need to learn how to know when to water. It needs to be when the plant actually needs it, not an arbitrary once a week (too often for these plants); or twice a month (my best guess as I grow these myself).

Glad to see your mix looks good, looks like it might drain well, which is helpful for these. Most often, folks fail w/ these due to overwatering.