This concerns the Assay definition imported from Columbus server. New Assay definitions are accessible from Spotfire Analyst. As well Assay definition on Plate level are accessible.
workaround: Go to the SImA and save the Assay definition with new name e.g. with suffix v2 and optionally delete the original. The newly saved Assay definition will be accessible in Spotfire Analyst.
Final correct: most probably this bug will not be corrected in the SImA at all.