Sherry asked from some pics of the aforementioned cells to see what the problem is, so I thought that I could share those pics with you too.
First the original Trustfire 26650 PCB 5000mAh that HKJ has tested on this thread: https://budgetlightforum.com/t/-/8149
and this is the one I received from Tmart:
Note the shape and gap around the +button, the difference in the yellow flame shape, the colour of the +TF26650 3,7 Li-ion- lettering above, silver on his and grey on mine.
Then note that the cell is shorter, both on top and bottom it misses the black portion present on the original ones, where the PCB disc and +contacts are.
The original cell measures 68,3 to 68,8 (depending on batch, apparently) meanwhile mine measures only 66,7. Missing the PCB, obviously. Weight is also lighter, 89g versus 92-94g for the originals.
Now the +button, on left the original protected, on right the Tmart one.
Bottom of cell, again on left HKJ tested original cell with PCB, and on right my cell without. The difference is pretty visible!
Next is comparison between labels, note that mine has a badly printed label with fuzzy fonts and colour overlappings between yellow letters and red flames.
original PCB
fake unprotected
detail:
Detail of bottom, clearly showing that there is no PCB
The cell charges and can be used, but without PCB protection and without knowing what kind of chemical the cell is (ICR, INR, ...) I would not feel safe to use it for prolonged periods.
Wonder if I should consider safe to use it in the HD2010. Being unknown brand 26650 cell, is it a safe assumption that being a 26650 sized, it can safely supply 3,4A to the driver without grenading?