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

Off the top of my ancient head:

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

General Introduction to Boundaries from Panahi Counseling:

What is the best case of “You just picked a fight with the wrong person” that you've witnessed?

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

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

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

Why was Boromir corrupted by the One Ring, but not Faramir in The Lord of the Rings?

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.

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

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

Emotional David Andrews says he didn’t want to play for any team other than the Patriots - NBC Sports

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

Serious disappointment when the client cancels a session.

Obsessing about clients outside of work hours.

Putin's uncompromising demands emerge after the latest round of Russia-Ukraine peace talks - AP News

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