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

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

Off the top of my ancient head:

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

Why do women stubbornly refuse to let men lead, even though they are attracted to the man, and the man both loves and desires them? Why do they get angry and blame the man when he gets fed up and walks away, when it's entirely their own fault?

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

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

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.

My boyfriend always verbally abuse me and makes me cry. If I try to tell him how hurt I was, he says to me he loves me and can't hurt me but always abuse me. Why?

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

Serious disappointment when the client cancels a session.

Obsessing about clients outside of work hours.

What is it like to wear a kilt?

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

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

General Introduction to Boundaries from Panahi Counseling:

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