Technically there is no regulatory time limit. The rule of thumb would be to conduct the training as close to the offense as possible, preferably within the same week of the offense. With that stated, other issues may prevent this such as field training, duty, etc. In cases like this corrective training should be implemented as soon as possible after the conflict is resolved.
I would also encourage leaders to follow the reasonable person rule. As the name implies: would this action sound reasonable to another leader if the Soldier challenged me on it?
If a Soldier believes they are being treated unfairly they should bring it to their supervisor’s attention in a calm and professional manner. If the supervisor is not responsive then see the platoon sergeant/platoon leader and/or 1SG/Commander on open door policy. If the Soldier is being mistreated most leaders will put a stop to the issue quickly. The question the Soldier needs to ask of themselves is: Am I being mistreated or am I whining?
Read The Mentor: Everything you need to know about leadership and counseling for more information about Counseling, Leadership, Corrective Training, and Separations in the Army.