Is the deferred delivery of local currency after the delivery of dollars, which occurred before going to prayer, considered a violation of the condition of immediate exchange (taqabud) and thus renders the transaction usurious, and what are the implications of this, especially since the amount was designated for Hajj?

What the questioner mentioned about parting ways with his colleague is considered to invalidate the قبض (seizure/possession) which is a condition for the validity of exchange (sarf); this is because it is a condition that the two counter-values be seized in the session before parting, otherwise the contract is void, and delaying either or both counter-values is forbidden as it constitutes riba al-nasi’ah (usury of delay). The solution now is for the questioner to return to his colleague the equivalent of what he took in local currency, and to receive back from him the equivalent of the dollars he paid, then they may exchange if they wish thereafter. This has no effect on the validity of Hajj.