Uber Technologies Inc. and Lyft Inc. continue to be their own worst enemy, according to a state lawmaker involved in negotiations over Texas-centric ridesharing regulations, even as the two companies and their armada of lobbyists sat comfortably in the driver’s seat this session as the regulations were crafted.

This session’s key ridesharing bill, House Bill 100, sailed out of the House earlier this month, with only a minor bobble: an ambiguous amendment defining gender. Spokesmen for Uber and…