New RA has trouble with includes()

I wrote a simple rule to automatically place incubator-raised slaves on speech correction until they have no accent, using the simple custom condition below:

AND ALWAYS BOOLEAN c=>((slave) => slave.origin.includes("aging tank") && slave.accent > 0)(c.slave)

The rule functions properly when applied to an individual slave from their Rules subscreen, but produces this file:// error when you press Apply Rules in the RA manager, as well as throwing a similar exception in the end-week RA report:

An error has occurred. You may be able to continue, but some parts may not work properly.

Error: Custom condition 'c=>((slave) => slave.origin.includes("aging tank") && slave.accent > 0)(c.slave)' failed: 'slave.origin.includes is not a function'.

Was able to rewrite the condition to do the job with other checks instead of the origin.includes(), but it would be nice to have that tool available.