The BytesTermAttributeImpl class, not used much I think, has a problem in its copyTo method in which it assumes "bytes" isn't null since it calls BytesRef.deepCopyOf on it. Perhaps deepCopyOf should support null? And also, toString(), equals() and hashCode() aren't implemented but we can do so.
This was discovered in
SOLR-8541; the spatial PrefixTreeStrategy uses this attribute and the CachingTokenFilter when used on the analysis chain will call clearAttributes() in it's end() method and then capture the state so it can be replayed later. BytesTermAttributeImpl.clear() nulls out the bytes reference.