I am not having this problem but my husband is. He, like most of us, switches back and forth between day and night mode. After switching to night mode, he was unable to go back to day, but only in tools, and only in some of them, not in texts.
If he is in day mode in a text, tools would be black on black and an attempt to switch to day mode in those tools would yield an immediate crash.
If he is in night mode in a text, the tools will display properly, night mode. Attempting to switch to day mode in some tools would still yield a crash. But he could switch between day and night modes in a text without a problem.
He tried deleting & reinstalling iAccord but the problem remained.
We compared our Accordance settings, and since the last tool he had opened was stuck in night mode, this is what his Tool Display page looks like.
IMG_0267.PNG 185.68KB 0 downloads
Just what we would expect when the iPad is in night mode.
We then opened one of the tools that would properly switch between day & night modes without a crash and set the Tool Display and had all options for text and background colors available. After saving those settings, the problem tools now can be switched without a crash. We now know how to fix this, but perhaps it would be a good thing to eliminate whatever glitch caused the problem?
We didn't check all tools, but a couple that did cause problems were Mounce's Basics of Biblical Greek and IVP Pocket Dictionary Series.
Our iPads are the same model (Air 1) with the same specs.