QUOTE:
What if you try to wipe just the folder of the affected timeframe instead?
I tried something like that but it doesn't work well because each time some symbols are randomly not updated correctly.
QUOTE:
We already have reports proving that this UPRO case is data corruption:
UPRO was just an example. As you can see the LastUpdateLog.txt attached, I ended up repeating update 4 times until I see no symbols are updated any more. 
Updating Daily data ...
IWM	0 bars	No data	0 bars added
UPW	0 bars	No data	0 bars added
URE	0 bars	No data	0 bars added
SCO	0 bars	No data	0 bars added
SDP	0 bars	No data	0 bars added
SDS	0 bars	No data	0 bars added
SIJ	0 bars	No data	0 bars added
SKF	0 bars	No data	0 bars added
SMN	0 bars	No data	0 bars added
SRS	0 bars	No data	0 bars added
SSG	0 bars	No data	0 bars added
TBT	0 bars	No data	0 bars added
TWM	0 bars	No data	0 bars added
BRZU	0 bars	No data	0 bars added
DRN	0 bars	No data	0 bars added
FAS	0 bars	No data	0 bars added
GASL	0 bars	No data	0 bars added
SPXL	0 bars	No data	0 bars added
TECL	0 bars	No data	0 bars added
TMF	0 bars	No data	0 bars added
TNA	0 bars	No data	0 bars added
TQQQ	0 bars	No data	0 bars added
Updating 1 Minute data ...
GDX	0 bars	No data	0 bars added in 2 chunks
QQQ	0 bars	No data	0 bars added in 2 chunks
SOXX	0 bars	No data	0 bars added in 2 chunks
SPY	0 bars	No data	0 bars added in 2 chunks
NUGT	0 bars	No data	0 bars added in 2 chunks
SPXL	0 bars	No data	0 bars added in 2 chunks
TMF	0 bars	No data	0 bars added in 2 chunks
YANG	0 bars	No data	0 bars added in 2 chunks
QUOTE:
 and download repeated.
 Even repeating the update doesn't fully solve the problem because there are symbols updated with much fewer bars. These symbols are supposed to have 40 to 80 chunks but only getting several chunks.
Updating 1 Minute data ...
DIA	79793 bars	2018/06/22 16:00	79793 bars added in 6 chunks
EEM	80158 bars	2018/06/22 16:00	80158 bars added in 6 chunks
FXI	95189 bars	2018/06/22 16:00	95189 bars added in 7 chunks
GDXJ	79703 bars	2018/06/22 16:00	79703 bars added in 6 chunks
IBB	62263 bars	2018/06/22 16:00	62263 bars added in 5 chunks
IWM	15990 bars	2018/06/22 16:00	15990 bars added in 2 chunks
QUOTE:
you might want to create a support ticket if interested.
Yes, I am interested.