Verges visual bug where they don't correctly show which colors they can tap for.
Before the April 1st pre-TDM update, verges used to show you which colors of mana that you could tap them to produce. Now, there is some kind of visual bug (or update?) that shows them being able to tap for both colors of mana, even when they can only tap for one color.
This tripped me up in a game where I was trying to leave 1 white mana open for Surge of Salvation, but it turned out that my land that looked white could only tap for green.
The screenshot is from an earlier game where I noticed the issue. I only have the Hushwood Verge and a Razorwood Thicket on the battlefield, but it looks like I can tap the verge for white.

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Altrivotzck#76830 commented
I also noticed that Mirrex was looking like a golden land, despite mutliple turns passing, so I'm assuming this problem applies to all lands that have dependencies on their color production.