Who is at fault?
Feels as though the issue was either a) TL approach to giving feedback or b) Agent approach to receiving feedback, or c) HR working hours (i'm with Zoe *grin*) - both a & b suggest a lack of appropriate training & support; c is the solution if you want to avoid addressing a & b
Constructive feedback well delivered is often far more effective if provided immediately off the back of the call. As Julian stated, you cannot limit monitoring to certain times or there is room for abuse. I have never considered it necessary for HR to be involved in feedback sessions.
It is important to seperate incidents when managing them - if the call warranted feedback only then the session should be strictly limited to that. If the feedback does not go well, and the TL feels it is appropriate, then I would recommend a halt to the meeting, with an agreement to reconvene for a formal session in line with the company disciplinary process. What cannot happen is that the feedback turns into a disciplinary, as this breaches all sorts of rights - formal notifcation, right to representation, etc.
If it is necessary to stop a feedback session then it is likely that the agent returning to the phones is a risk, and therefore it may be necessary to suspend the agent on full pay & without prejudice pending the formal disciplinary process. I have experienced this both as a TL, and as senior management where a TL initiated the suspension - if well handled this is perfectly acceptable practice and often helps to difuse the situation by giving parties breathing space.
This comes down to support & training of the TL to do their job - if the company is not comfortable that they have trained their managers to an acceptable standard to be able to handle core capabilities then the company needs to do something about it! Financial & other regulated industries require proof of competence for managers. If the company is unable to develop its management team to an acceptable (for the company) level of competency then it needs to provide core services such as HR throughout the operational opening times
Obviously, every individual situation is different, but the skill of a team leader is to be able to manage their team both transparently, and in a way that acknowledges them as individuals and tempers business imperative with humanity.
...IMHO of course! ;o)
[Edited by JTC to fix hanging underline tag, 121004/1705]