Unable to parse decoded base64 data as JSON

Applied a 20k op/sec load:
run workload --get 50 --create 12 --update 30 --delete 8 --ops 20000

sample 512byte document template:

{
"padding": "456GDVRHLDIZA6LB1MS8F90WZRB1CQQ2DKWCOYOTHBYPXAF0NY2ER6GO6OHFO8UI0EHSP7KCKIERSPKRDOUF1MNHPS9XPLW08494SN0XANL2HAGSH2DVI1SBPWBX0LJR4K34IFQHDD74MK5VPYXEEW325L25TC87E44JUXY9RIL6DNF2W1A6JE7N72R58ROG9PB6N6IS5BS6MVIZB8TD1PTNQHHOG0VLH64FO0JZW1FEKU3MY2C4KF1SD12X709BWSRQCZKPKYZ9HSYQKUXCFH6RB2ELU1EM06VE9LU27URVLWO43LL4TF1YUBYJZ84V5DCMGX089YQZHC30CLPDF8MT1423NHUW80F2SJHEA8J5WJ4HJL9EQKD077ET712PYUXGFOR98QZDFPQ2C8FRQC44Z4SIMIBCD03EB6Z6EGYSI10VJBIQCOH024Q1LYEWTABAG74ZQQ22KJW78UPN2IBE4N57B",
"city": "mateo",
"list": [
1,
2,
3
],
"hello": "world",
"map":

{ "sample": "map", "complex": 1 }

}

and observing the following errors in logs:

[2013-01-21 16:05:56,005][ERROR][transport.couchbase.capi ] [Omega Red] Unable to parse decoded base64 data as JSON, indexing stub for id: D963FBCB91C6037390BB6404
[2013-01-21 16:05:56,006][ERROR][transport.couchbase.capi ] [Omega Red] Body was: �)+k^K^@^@@^@@^@@^@@^@@^@@^@@^@@^@@^@@^@@^@ Parse error was: org.codehaus.jackson.JsonParseException: Unexpected character ('ð' (code 240)): expected a valid value (number, String, array, object, 'true', 'false' or 'null')
at [Source: [B@42ff1c7f; line: 1, column: 2]
[2013-01-21 16:05:55,787][TRACE][com.couchbase.capi.servlet.CAPIServlet] Got bulk docs request for default/988;00000000000000000000000000000000
[2013-01-21 16:05:55,786][DEBUG][transport.couchbase.capi ] [Omega Red] Bulk doc entry is [{meta=

{id=DB55C88BCF4D5242B5EF15E7, rev=1-00448c25e6d518f20000000000000000, expiration=0, flags=0}

, base64=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}, {meta=

{id=A49129193F3E5B5A733D9C1A, rev=4-00448c278e0946e20000000000000000, expiration=0, flags=0}

, base64=eyJwYWRkaW5nIjogIk5QUlFGOVdNTDBFQkVCUU0zS0NVNVo3VU9ZMkRKVllDWEsyRlFCWTBPREhMUzRPTjJZRk5VSzczNkc4QlRLRFM1T0pQNkZHRjEzQ0FZRFE3MVpLSDJEVzlWTElQUTJWTFFHS1lPTFlQQTZaQUlOTThOUzUxSzdYVFBIT1o2RkxKUThJOFpQV003NE1MSTFYOTkxVENRMTZZUlBZNFlKRTZTN0NZS1czSDZJRzY0SzNVMEw4MjIwSk42R1Y4TjVUTVhDN0lORDBZU1I4SlM2Uk82UkpXRFRaUUNJWUhMRlY4V1U2VjNaU0NZN0lWS0xZVU9WWFFHS0ZXOUU4WVA2Q1RRSDJSTUJVNjI4M0ROMkZSVUJIR1FVV1c2R1NCVExVRzg4MDJKOEszSVcwTEpZREJIQjZYME5VNExKMTRETDNMREQ4SjUwRTVLTEdEOFZMQlk0VkJPOVU2TVhZM085UjFOS1ZMWkdGVFc3MjUxUlU4VEkzSkNCRkI4WkU1NE8yWFkyV0pMV0cxMlFRTEg3WjFQUUhTUDhSTzlYT1hVRFBQU01ZQTYxSUFYQ05ESUVGT1IzNzhaWVVYNlIwU01XSTdIVjAxMVozQ0w5SldDUVZXVEpTS0VMTFVUWFQ2NyIsICJjaXR5IjogIm1hdGVvIiwgImxpc3QiOiBbMSwgMiwgM10sICJoZWxsbyI6ICJ3b3JsZCIsICJtYXAiOiB7InNhbXBsZSI6ICJtYXAiLCAiY29tcGxleCI6IDF9fQ==},