The ability to transfer players is never halted. It simply rolls over to the next round. Round 12 transfer deadline was 7:15 pm EDT Wednesday May, 15th , any transfers after 7:15 PM on Wednesday would be attributed to week 13. Some people are setting their teams up for next weeks round early or they didn't realize that the transfer deadline was actually Wednesday rather than what would normally be Saturday (I think this is the case in some of the transfers in this situation).
On occasion I have taken a gamble with hot players who's value is on the rise and transferred early to take advantage of lower values. This is risky since he may not have played during the round at that point and there is a possibility of being injured while you have already burned your transfer for the next round.
The increase in value for a player is based on transfers in and out to make up a net transfer number. When that number represents 1.8 percent of the overall managers in the league there will be a change of $0.1M. That number (1.8%) is adjusted when a player is injured, as in the case of Keane.
Link to MLS FSM explanation.
I'm not convinced that the 1.8% is based on the overall managers in the league as suggested by the FSM organizers. I think it might be based on the percent of owners for that particular player. I currently have Quillan Roberts as my backup keeper. He has a net transfer of -23. He has dropped in value $.02M. 23 does not represent 1.8% of overall managers in the league. That number would be 392 based on 21 832 players. So I really do not know exactly how value is calculated.