This can be indirectly reproduced by running CE-Symm on d2iolb_ from a34b1bb (before the length check was introduced in d7133ca2). It will produce a out of bounds error after iterating down to the minimum subunit.
Fixed in d365f3f. The bug was solved by allowing missing information in AFPChain when CeSymm cannot find a meaningful alignment and returns an empty array.
This can be indirectly reproduced by running CE-Symm on d2iolb_ from a34b1bb (before the length check was introduced in d7133ca2). It will produce a out of bounds error after iterating down to the minimum subunit.