trying to avoid having poudriere recompile rust every time it runs

Is there a method or workaround where poudriere avoids recompiling
rust every time it is run?

There is no poudrierejail-make.conf present.

There are no options set for rust. In other words, the options
are the defaults. rust is on FreeBSD's pkg servers rust-1.72.0

I'd expect poudriere to pull down the ready-make pkg. The
rust poudriere tries to build is also rust-1.72.0
The Makefile for rust in the ports tree of 30 mins ago
that poudriere uses also reports this version.

No other pkg that I'm aware of behaves like this. 

system: rpi4/8GB stable/14-n265383 arm64 1400500 1400500
poudriere-devel-3.3.99.20220831_3 

relevant poudriere.conf entries
PACKAGE_FETCH_BRANCH=latest
PACKAGE_FETCH_URL=pkg+https://pkg.FreeBSD.org/\${ABI}
#PACKAGE_FETCH_BLACKLIST=""
#PACKAGE_FETCH_WHITELIST="gcc* rust llvm*"
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