Q1: Because when the block is found the node informs its peers that it found a new block, but not telling the block to the peers. Then it is peers responsibility to pull the block itself from that node. This has certain latency that depends on two factors - the network latency and the participating nodes performance and current load.
Q2: because the target time is 30 seconds while the delays in propagation are quite big, so the probability of two blocks found in the same time period required to propagate the block over the network is higher than the same probability for litecoin, for example. I can't recall if it was proposed in regard to the Grain or some other coin, but the idea was to double the target time instead of forthcoming reward halving. This proposed solution should lower the orphan ratio.
about Q2,
I have tracked my debug.log file, from xx:50:00
at xx:50:23 Received block 0000000f275e14b8fdb
xx:50:24 Received block 00000009f2f6774c316
xx:50:25 Recieved block 3b4a224dc17a785d8fbe <- PoW
xx:50:25 Reorganized
new best is the matched with the previous block of #159016
xx:50:43 I have found a block
xx:51:21 orphans
My computer report, I found a block #159016 at xx:50:43(and got feedback on xx:50:49), it is declare the block is orphans on xx:51:25
the block has been connected at xx:50:19, and other block is connected on xx:51:21
: The block has been found on xx:50:19
: QT just reorganize the block on xx:50:21, and there is no noticed, it indicate the old chain yet
: my computer waste time till xx:50:43, and found the next block
: got feedback from some body on xx:50:49
: on xx:51:21, it has notified about #159016 has found already,
: on xx:51:22, reorgainze the block chain, and my founds are become orphans,
(1) I just lost 30 seconds (xx:50:19 ~ xx:50:49), till I found a new block,
(2) It has been fixed on xx:51:21,
Maybe, it will takes a time to decide as an orphan block, it can takes a time sometime (xx:50:49~xx:41:21, 33 seconds)
I am not sure,
Is it the normal situation ?
I have to lost 61 seconds till I got the notification about #159016 which has found 62 seconds ago ?
The height of block racing can be happen with extremely low diff and large hashes,
becuase of there is no time gap to share the information between QTs
Is it possible on this coin now ?
and, such a frequently ?
To process a block how long latency will be needed ?
I can agree about explaination, because of your explaination is absolutely right,
but, my question is it is not fit on the current situation,
if there are couple of seconds of time-gap, maybe yes,
but, there are 20-30 seconds of time-gap, and didn't aware somebody found a new block ?
and, fixed after next block ?
I can not agree it is normal,
If just happen once, maybe I can say, even difficult but can happen,
but, it is happen 2-3 times every hours ?
AGAIN, I do not talk about Techincally Possible or Not,
Becasue of technically possible,
But, I am asking Why too frequently ?
Anyway, the dev think it is normal for this coin, and it is normal.
and, I remebered the dev say this is normal. so, at least, it is normal for this coin,
so, I do not want to mention about it again,
