What has held back solar ETFs?

E.g. Invesco Solar Energy is down 3% YTD.

The IRA is supposed to be a major boon for solar.

From a recent AP news article: “sales at the largest manufacturer of solar panels in the U.S., First Solar, skyrocketed after the law passed, creating a big backlog of orders”.

So what's keeping share prices down? Is this industry particularly affected by the interest rate environment? How is e.g. a 30% federal discount on rooftop solar not finding its way to earnings and by extension price action?