[Dovecot] doveadm search not showing expected results

[btb at bitrate.net]

i'm running doveadm search:

>doveadm search -A mailbox sent savedbefore 365d
>

and it's returning no results.

a similar command does return some results:

>doveadm search -A mailbox sent savedbefore 120d | grep -iF 'jdoe'
jdoe 7b9a8b0b7d37504fe72c000055e4fe9a 65
jdoe 7b9a8b0b7d37504fe72c000055e4fe9a 66
jdoe 7b9a8b0b7d37504fe72c000055e4fe9a 67
jdoe 7b9a8b0b7d37504fe72c000055e4fe9a 68
jdoe 7b9a8b0b7d37504fe72c000055e4fe9a 69
jdoe 7b9a8b0b7d37504fe72c000055e4fe9a 70
jdoe 7b9a8b0b7d37504fe72c000055e4fe9a 71
jdoe 7b9a8b0b7d37504fe72c000055e4fe9a 72
jdoe 7b9a8b0b7d37504fe72c000055e4fe9a 73
jdoe 7b9a8b0b7d37504fe72c000055e4fe9a 74
[...]

however, i see many messages in the sent mailbox much older than 365 days:

>l ~jdoe/mail/Maildir/.sent/cur/
total 82M
-rw------- 1 jdoe jdoe  411 Jul 12  2011 1310503747.M652859P14078.flip,S=411,W=423:2,S
-rw------- 1 jdoe jdoe  515 Jul 12  2011 1310523810.M800998P5307.flip,S=515,W=530:2,Sgh
-rw------- 1 jdoe jdoe 1.4K Jul 17  2011 1310922140.M604706P14587.flip,S=1339,W=1378:2,Sgh
-rw------- 1 jdoe jdoe 2.7K Jul 17  2011 1310955899.M58727P3373.flip,S=2731,W=2814:2,Sgh
-rw------- 1 jdoe jdoe 4.1K Jul 18  2011 1311032789.M471208P19367.flip,S=4162,W=4284:2,Sgh
-rw------- 1 jdoe jdoe  451 Jul 22  2011 1311363858.M21157P19993.flip,S=451,W=464:2,Sgh
-rw------- 1 jdoe jdoe  461 Jul 23  2011 1311436347.M315008P29267.flip,S=461,W=474:2,Sgh
-rw------- 1 jdoe jdoe 1.6K Jul 26  2011 1311731312.M902135P25749.flip,S=1607,W=1655:2,Sgh
-rw------- 1 jdoe jdoe  888 Jul 31  2011 1312161704.M81319P3943.flip,S=888,W=911:2,Sgh
-rw------- 1 jdoe jdoe  676 Aug  4  2011 1312512384.M809375P3684.flip,S=676,W=692:2,Sgh
-rw------- 1 jdoe jdoe  556 Aug  6  2011 1312669537.M999983P18243.flip,S=556,W=571:2,Sgh
-rw------- 1 jdoe jdoe 1.8K Aug  7  2011 1312737844.M921026P22678.flip,S=1769,W=1817:2,RSgh
-rw------- 1 jdoe jdoe 2.5K Aug  8  2011 1312842718.M632088P24434.flip,S=2489,W=2559:2,Sgh
-rw------- 1 jdoe jdoe 2.3K Aug 10  2011 1312997501.M29900P8705.flip,S=2254,W=2306:2,RSghi
-rw------- 1 jdoe jdoe 1.2K Aug 10  2011 1312998375.M806199P8705.flip,S=1200,W=1223:2,S
-rw------- 1 jdoe jdoe 2.8K Aug 10  2011 1312998687.M179687P8705.flip,S=2857,W=2931:2,S
-rw------- 1 jdoe jdoe 1.9K Aug 10  2011 1313017076.M909199P8264.flip,S=1889,W=1941:2,Sgh
-rw------- 1 jdoe jdoe 2.8K Aug 12  2011 1313172631.M470122P23201.flip,S=2822,W=2895:2,RSgh
-rw------- 1 jdoe jdoe 3.3K Aug 16  2011 1313502988.M870415P19669.flip,S=3333,W=3413:2,RSghi
-rw------- 1 jdoe jdoe 3.4K Aug 16  2011 1313523978.M484997P19669.flip,S=3447,W=3534:2,S
-rw------- 1 jdoe jdoe  939 Aug 16  2011 1313545488.M796759P21368.flip,S=939,W=968:2,Sgh
-rw------- 1 jdoe jdoe 3.9K Aug 17  2011 1313600016.M183385P25953.flip,S=3989,W=4092:2,S
-rw------- 1 jdoe jdoe 1.3K Aug 22  2011 1314028430.M280232P10201.flip,S=1291,W=1326:2,S
-rw------- 1 jdoe jdoe  943 Aug 22  2011 1314067361.M643189P1408.flip,S=943,W=967:2,Sgh
-rw------- 1 jdoe jdoe 1.1K Aug 23  2011 1314114645.M26643P14083.flip,S=1108,W=1142:2,S
-rw------- 1 jdoe jdoe  932 Aug 24  2011 1314237640.M473097P22476.flip,S=932,W=954:2,Sgh
-rw------- 1 jdoe jdoe 5.8K Sep  1  2011 1314900538.M22534P26553.flip,S=5851,W=5976:2,Sgh
[...]
-rw------- 1 jdoe jdoe  423 Feb 17 13:00 1361124040.M492223P13245.xenon,S=423,W=436:2,Sab
-rw------- 1 jdoe jdoe  423 Feb 17 13:02 1361124143.M127879P13245.xenon,S=423,W=436:2,Sab
-rw------- 1 jdoe jdoe  412 Feb 17 14:13 1361128391.M812807P13644.xenon,S=412,W=425:2,Sab
-rw------- 1 jdoe jdoe 1.6K Feb 18 21:12 1361239930.M525334P20966.xenon,S=1621,W=1660:2,Sab
-rw------- 1 jdoe jdoe  422 Feb 19 20:53 1361325222.M901235P32184.xenon,S=422,W=435:2,Sab
-rw------- 1 jdoe jdoe 1.8K Feb 19 21:06 1361325990.M129075P32180.xenon,S=1818,W=1864:2,Sab
-rw------- 1 jdoe jdoe  424 Feb 19 21:13 1361326428.M381244P32180.xenon,S=424,W=437:2,Sab
-rw------- 1 jdoe jdoe  424 Feb 19 21:22 1361326968.M84809P32180.xenon,S=424,W=437:2,Sab
-rw------- 1 jdoe jdoe  424 Feb 19 21:24 1361327050.M328090P32180.xenon,S=424,W=437:2,Sab
-rw------- 1 jdoe jdoe  424 Feb 19 21:25 1361327139.M963578P32180.xenon,S=424,W=437:2,Sab
-rw------- 1 jdoe jdoe 1.3K Feb 20 08:23 1361366627.M318860P22786.xenon,S=1230,W=1260:2,S
-rw------- 1 jdoe jdoe 3.0K Feb 20 10:44 1361375042.M340353P5202.xenon,S=3019,W=3082:2,S
-rw------- 1 jdoe jdoe 1.1K Feb 21 09:09 1361455754.M925454P13135.xenon,S=1025,W=1048:2,S
-rw------- 1 jdoe jdoe 1.4K Feb 21 11:18 1361463526.M927071P13133.xenon,S=1344,W=1376:2,S
-rw------- 1 jdoe jdoe 1.6K Feb 23 11:14 1361636078.M972572P18385.xenon,S=1636,W=1672:2,Sab
-rw------- 1 jdoe jdoe 1.5K Feb 23 11:26 1361636803.M56491P18385.xenon,S=1490,W=1524:2,Sab
-rw------- 1 jdoe jdoe 2.2K Feb 24 14:25 1361733929.M725648P18385.xenon,S=2178,W=2229:2,Sab
>

i do see these older messages properly listed and viewable in my imap client.  how can i figure out what i'm doing wrong, and troubleshoot why doveadm doesn't seem to consider these message as matching?

thanks
-ben