The original transfer rule was one per use year, but a transfer was defined in the DVC Membership Agreements and Home Resort Rules and Regulations as: "Transfer shall mean the assignment by one Club Member of the use of his or her Home Resort Vacation Points to another Club Member during a given Use Year." That is still the definition of a transfer in both such documents. That definition seemingly does not prohibit a member from doing multiple transfers between his own memberships. DVC's position otherwise would be the argument that either (a) a club member who owns two memberships is actually two different club members, or (b) the transfer rule is absolute in that a member cannot transfer points between the member's own memberships because the transfer rule allows only transfers between different club members.
As far as I am aware, DVC has always allowed, until earlier this year, a member to do more than one transfer between the member's own memberships. I recall seeing mention of that fact in posts in the early 2,000s. I learned of the new "rule" that a member's transfer between the member's own memberships is subject to the one transfer rule via a telephone call with MS in April 2025 when I did a transfer between my memberships, and apparently others have had similar conversations. I have not actually seen DVC's formal issuance of any such new rule or any document that has expressly changed the definition of a transfer in the Membership Agreements or Home Resort Rules.
Note also that though the original transfer rule was one transfer per use year, that rule itself was actually changed in the early 2,000s to allow any member to do an unlimited number of transfers in any use year as long as all the transfers were in one direction, i.e., the member could transfer out multiple times, or transfer in multiple times, but not do both in any given use year. That rule change actually contributed to professional renters being able to do many rentals as they could use their own points to do rentals and do deals with many members to have them transfer points to the professional renter member who would then use them to do rentals. Rentals became a problem because the professional renters were using lots of points, including transferred points, to reserve times that were highly desired such as first two weeks of December, Christmas week and other holiday times. In about 2007, DVC returned to the original transfer rule of one in or out per use year, but it did not stop allowing members to transfer multiple times among their own memberships.
The new rule, if there actually is one, to limit members to only one transfer per use year between the member's different memberships appears to be another one done to decrease professional renter activities. If there is such a new rule, I question its validity because the transfer definition does not prohibit a member from doing multiple transfers among the member's own memberships. The rule DVC should be enforcing, but apparently has not done so in the past, is the rule stated in the Home Resort Rules and Regulations, §II(6)(k) which states: "Club Members are expressly prohibited from receiving any compensation for engaging in any transfer activity." Perhaps making a member who is requesting a transfer to confirm at the time of such request that there is no compensation involved with the transfer, and providing some penalty if DVC learns the confirmation made is false, such as cancelling any reservation made using the points, is something DVC should consider doing..