What are some signs that a therapist may have poor boundaries with their clients?

Serious disappointment when the client cancels a session.

Off the top of my ancient head:

Routinely going over the time limit with certain patients, compromising the time for the next client.

The Toyota Supra Won't Stay Dead For Long - Motor1.com

These items can happen fleetingly, briefly, in any therapy, but if they’re frequent, it’s definitely time for the therapist to get some good, solid supervision/consultation.

Session-expressed curiosities about client details not relevant to the therapy.

Frequent phoning or texting of clients to “check up on them and make sure they’re OK.”

Ending Parole for 500,000 Migrants Creates New Headaches for Employers - WSJ

Eager anticipation (or anxious anticipation) of the next session in ways that distract.

Struggling with fantasies of deeper connections with clients, whether sexual or parental or other intense or intimate relationships beyond psychotherapy.

General Introduction to Boundaries from Panahi Counseling:

Harvard gastroenterologist ranks popular trends: Is eating cold rice, doing intermittent fasting good for gut health? | Health - Hindustan Times - Hindustan Times

Obsessing about clients outside of work hours.

Sense of competition with persons who are important in the client’s life.

Failing to mention the client in supervision/consultation, out of fear the supervisor/consultant will advise return to ordinary healthy boundaries.

Why stablecoin play Circle’s stock is still a buy even after a sixfold rally - MarketWatch

Disclosing feelings, fantasies, and experiences to the client in ways not related to the work the client is engaged in.