Looks like the problem it's related with inserts in a specific TABLE. The insert by itself does not have notthing special about it:
INSERT INTO "CUBE_f21317a4f3e34fd895de2fa6c1d07310_FACT"("ID",
"CUBE_LOAD_ID",
"INSERT_DATE",
"UPDATE_DATE",
"ATTR_3d82e2b7ea1b44c1b43715811e10164a",
"ATTR_9eb89b711aaf4c62bc1a4615e36d51b3",
"ATTR_ba67d32fde6e47058cd0b704fca4c4dc",
"ATTR_8e8f1274dbf94a53ba82506ef2ce27bb",
"ATTR_73ffb9de993d4a4889ce0400d39a5f8a",
"ATTR_e7e7e6975e7d4e54b74f49da611aad93",
"ATTR_086c1b52010d4871abce83bc904ef173",
"ATTR_ea58cc1de0ad4314a31f2c2af6203de4",
"ATTR_6c6d1a98a9cd42aa872d0be7de9807eb",
"ATTR_162e3b62abd446dd9f21251bb67ca8e1",
"ATTR_e912e91c81a144398e071e51576171a4",
"ATTR_97b6e5c8fb3b43e1ac9beadeb6b1fbee",
"ATTR_cbb2c319a54d4bd4a2ba625fb12b7fb3")
values(:primaryKey
,:cubeLoadId
,:insertDate
,:updateDate
,:3d82e2b7ea1b44c1b43715811e10164a
,:9eb89b711aaf4c62bc1a4615e36d51b3
,:ba67d32fde6e47058cd0b704fca4c4dc
,:8e8f1274dbf94a53ba82506ef2ce27bb
,:73ffb9de993d4a4889ce0400d39a5f8a
,:e7e7e6975e7d4e54b74f49da611aad93
,:086c1b52010d4871abce83bc904ef173
,:ea58cc1de0ad4314a31f2c2af6203de4
,:6c6d1a98a9cd42aa872d0be7de9807eb
,:162e3b62abd446dd9f21251bb67ca8e1
,:e912e91c81a144398e071e51576171a4
,:97b6e5c8fb3b43e1ac9beadeb6b1fbee
,:cbb2c319a54d4bd4a2ba625fb12b7fb3)
Restarting MonetDB temporarly solves the problem. I can collect some additional info, just point me where to.