MoreLikeThis query parser can not fetch document with id using implicit router

[r ohara <ro...@gmail.com>]

We are using the SOLR 8.9 in cloud mode and having issues getting results
with the MLT query parser. We get this error  "Error completing MLT
request. Could not fetch document with id "

We're using an implicit router field for sharding, so it looks like this
same issue I found from 2017 here:
http://mail-archives.apache.org/mod_mbox/lucene-solr-user/201704.mbox/%3C1492518046754-4330485.post@n3.nabble.com%3E
 "We've bumped into this issue too, but it was through the MoreLikeThis
query parser. Internally it uses the get handler to obtain the seed
document. One of our SOLR collections uses a shard router that is not the
document id. The get handler will fail if the value of the document id is
not the same as the routing key. And then this causes the CloudMLTQParser
to issue the message "Error completing MLT request. Could not fetch
document with id [/x/]"

Can we not use the MLT query parser if we're using implicit router
sharding? Any suggestions would be appreciated.

Thanks in advance