Running the following commands creates the stabilizing_branch uprev commit in chromiumsos-overlay but the CROS_WORKON_TREE value for platform2 is invalid and also there are two of them. 

$ cros_mark_as_stable --force -p dev-util/puffin -o ../src/third_party/chromiumos-overlay/ -- commit

-CROS_WORKON_COMMIT=("a14582f5b2ae17da4bbc7b5d887d601dbb407a2" "f0bad1d0035d5045eac9d9e895239fc712d07715")
-CROS_WORKON_TREE=("43f50f314fa9a22ac645b844e0e9f4abe31a4f4e" "38ea516577da057fb423c69fa98d17fcb0d053d8")
+CROS_WORKON_COMMIT=("80c7b00e09f0505d39a7848e8e8311a7c6574d85" "dfec7fab93efd097fa494268d0e60e7e115dcea7")
+CROS_WORKON_TREE=("701558aea91962850a47beaf36575d78ab77940f" "dc1506ef7c8cfd2c5ffd1809dac05596ec18773c" "9b31a005af654c8d652f4aebebf840cfb42879c8")


$ cd src/aosp/external/puffin
$ git log -1 --format=%T
9b31a005af654c8d652f4aebebf840cfb42879c8 

which is correct

$ cd src/platform2
$ git log -1 --format=%T
b669d122c480efd9e29ebcc55e0cb1959318dae3

which is not equivalent to either "701558aea91962850a47beaf36575d78ab77940f" nor "dc1506ef7c8cfd2c5ffd1809dac05596ec18773c"