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

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

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:

Do flat Earthers really exist? Why do they believe the Earth is flat?

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.

Obsessing about clients outside of work hours.

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

Why does my vagina smell sort of fishy/musty days after sex when my boyfriend ejaculates in me? There isn’t any itching or burning when urinating, so I don't think I have BV. It just doesn't smell like me.

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

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

Off the top of my ancient head:

Researchers Unlock An ‘Alien’ Phenomenon Under Earth’s Largest Lithium Reserves - The Daily Galaxy

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

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

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

‘Titan: The OceanGate Disaster’ Review: The Horrors of Hubris on Netflix - WSJ

Serious disappointment when the client cancels a session.