Q: sync stop and Deferring

HI:
where I inspect sg logs, I finded a lot of deferring message:

2019-05-17T11:03:35.721+08:00 [INF] Cache: Deferring #107148 (18 now waiting for #107134#107135)
2019-05-17T11:03:35.721+08:00 [INF] Cache: Received #107153 after 102ms (“Order.928cec25-de8b-4edb-bba6-cfa38a43d0a7” / “5-219823294ffa9e4da8387a36d0dd9040”)
2019-05-17T11:03:35.721+08:00 [INF] Cache: Deferring #107153 (19 now waiting for #107134#107135)
2019-05-17T11:03:35.722+08:00 [INF] Cache: Received #107156 after 96ms (“Order.96178466-3c39-49bb-b626-e3d9b7c22fbd” / “2-6ed807cc665712a35f91c937617b6a0e”)
2019-05-17T11:03:35.722+08:00 [INF] Cache: Deferring #107156 (20 now waiting for #107134#107135)
2019-05-17T11:03:35.723+08:00 [INF] Cache: Received #107162 after 84ms (“Order.97563459-c655-4bc8-8f1a-0be684f83460” / “6-25af9aa93e0c19151c2e04e6c353ca38”)
2019-05-17T11:03:35.723+08:00 [INF] Cache: Deferring #107162 (21 now waiting for #107134#107135)
2019-05-17T11:03:35.724+08:00 [INF] Cache: Received #107164 after 81ms (“Order.9c0cd527-f0fd-49a9-8f50-65d427f330ce” / “3-dd1f3cbc71989ec8e8d3573122a7b8b7”)
2019-05-17T11:03:35.724+08:00 [INF] Cache: Deferring #107164 (22 now waiting for #107134#107135)
2019-05-17T11:03:35.725+08:00 [INF] Cache: Received #107167 after 73ms (“Order.a40e5665-236d-4dc8-b50f-f03717eafc04” / “3-bb63ec7048e1b815025a7cf3ca0bcdc0”)
2019-05-17T11:03:35.725+08:00 [INF] Cache: Deferring #107167 (23 now waiting for #107134#107135)
2019-05-17T11:03:35.727+08:00 [INF] Cache: Received #107169 after 51ms (“Order.a8cb5d6b-351b-4fd9-86af-cd43df9dcd2c” / “3-de4e469bd6d9b085c6c69dc5dfa7a920”)
2019-05-17T11:03:35.727+08:00 [INF] Cache: Deferring #107169 (24 now waiting for #107134#107135)
2019-05-17T11:03:35.727+08:00 [INF] Cache: Received #107171 after 45ms (“Order.aca17b9a-e6bf-4e48-8068-9b921f2a413a” / “3-20977e3426dadf48ff647342391c7edb”)
2019-05-17T11:03:35.727+08:00 [INF] Cache: Deferring #107171 (25 now waiting for #107134#107135)
2019-05-17T11:03:35.727+08:00 [INF] Cache: Received #107173 after 41ms (“Order.d4820830-ccb0-4419-830b-c6e293627a5a” / “2-59d9d73da54014d0059f10880c37b2cf”)
2019-05-17T11:03:35.727+08:00 [INF] Cache: Deferring #107173 (26 now waiting for #107134#107135)
2019-05-17T11:03:35.728+08:00 [INF] Cache: Received #107177 after 36ms (“Order.d6230ee4-c4b5-4349-b2d7-effccd17e70c” / “4-6abb509867e3e6fbb72d737f647bdf3d”)
2019-05-17T11:03:35.728+08:00 [INF] Cache: Deferring #107177 (27 now waiting for #107134#107135)
2019-05-17T11:03:35.729+08:00 [INF] Cache: Received #107178 after 34ms (“Order.e910ec69-17f3-498f-a6eb-8da44e4a2573” / “2-6ea253e0ba73eea6d92d49fe34f3bc1b”)
2019-05-17T11:03:35.729+08:00 [INF] Cache: Deferring #107178 (28 now waiting for #107134#107135)
2019-05-17T11:03:35.729+08:00 [INF] Cache: Received #107180 after 28ms (“Order.eb4a2f61-bab7-488b-9e2e-2f927d056622” / “4-cfee4b89aa32ec679ab388c2e23cb230”)
2019-05-17T11:03:35.729+08:00 [INF] Cache: Deferring #107180 (29 now waiting for #107134#107135)
2019-05-17T11:03:35.730+08:00 [INF] Cache: Received #107182 after 16ms (“Order.fdfecc22-71ff-48bd-ab79-8655a490acac” / “5-1baab35114c619d5137cf02db5c548e3”)
2019-05-17T11:03:35.730+08:00 [INF] Cache: Deferring #107182 (30 now waiting for #107134#107135)
2019-05-17T11:03:35.733+08:00 [INF] Cache: Received #107134 after 175ms (“Order.41b57a11-e062-4918-8592-9ce4344af172” / “4-f9a81c735ef0df288dd89cfb0b965543”)
2019-05-17T11:03:35.733+08:00 [INF] Cache: #107134 ==> channel “733d2f51”
2019-05-17T11:03:35.733+08:00 [INF] Cache: #107134 ==> channel “*”
2019-05-17T11:03:35.733+08:00 [INF] Cache: getCachedChanges(“733d2f51”, 107133) → 1 changes valid from #107134

this is a normal message? can I ignore it?

and today I testing my app, occurred not sync. the lite logs is:

db—MsgGoods.645c5bf3-11a7-45aa-83dc-16e24ced6017
05-17 11:38:53.176 4524-4575/com.kitchenmanage.kitchenmanage E/LiteCore [Sync]: {Push#3} Proposed rev ‘MsgGoods.645c5bf3-11a7-45aa-83dc-16e24ced6017’ #3-fdfbad56c5d5a291215b7c7b6094e4caa90d1816 (ancestor ) rejected with status 409
05-17 11:38:53.176 4524-4576/com.kitchenmanage.kitchenmanage E/C4Replicator: documentErrorCallback() handle → 2023813336, pushing → true, docID → MsgGoods.645c5bf3-11a7-45aa-83dc-16e24ced6017, domain → 6, code → 409, internalInfo → 1033, trans → false

I delete android local couchbase lite database, then pull whole data again. after about 5mins, the sync became normal.

my env is:
cb server 6.0.1
cb lite: 2.5
sg : 2.5

Best regards

angular