Reindex error with Amasty Elasticsearch engine

Reindex error with Amasty Elasticsearch engine

I am on Magento 2.4.5-p1. When I reindex, I get the following error when using Amasty elastic search engine (recently updated version 1.16.2). the error disappears if I use the default Magento elasticsearch or if I downgrade to Amasty elasticsearch version 1.16.1. 

Catalog Search index process error during indexation process:
{"error":{"root_cause":[{"type":"runtime_exception","reason":"Invalid Mapping Rule : []"}],"type":"runtime_exception","reason":"Invalid Mapping Rule : []"},"status":500}