conda installs (or update/upgrades) into the current environment deactivate and reactivate all packages, including eups, now that it is in conda. Because eups thinks it owns the EUPS_PATH environment variable, the reactivation leaves it pointing into the environment's stack instead of the external stack created by lsstsw/deploy or newinstall.sh.

The simplest fix for this, as suggested by Matt Becker, is to have envconfig and loadLSST set another environment variable, LSST_EUPS_PATH, and to have the rubin-env activation script prefix the value of that variable, if present, to EUPS_PATH. (Since rubin-env luckily happens to be after eups alphabetically, it can do this safely.) Then deactivations and reactivations will result in the same, usable EUPS_PATH since LSST_EUPS_PATH will persist throughout.