Recommend buying from Chip_Partner, ICs_Processors or RMM (usa BLF seller).
I just noticed there are now some boards on ebay with a different chip, marked “TP4056” but lack the stylized TP logo. Seems to be the cheapest $1 boards on ebay. Have to love chinese companies. 
<img src=http://i.ebayimg.com/t/1pc-5V-Micro-USB-1A-1000mA-Lithium-Battery-Charging-Board-Charger-Module-/00/s/NjAwWDYwMA==/z/JTwAAOxyBXNSVO-m/$T2eC16h,!zIFIeoE4OF-BSVO-kYP7g~~60_1.JPG>
I would guess these chips (without TP logo) are likely Tapower “tp4056” chips. Pavithra_uk reports that he has one & it seems to behave different.
Original tp4056 NanJing Top Power chip. Datasheet
The chip that HKJ tested. Also pictures that others posted have all shown this chip.
I’ve bought from Chip_Partner and ICs_Processors for $1.54. Always received original tp4056 Top Power chips. RMM now has them for $1.42. Once brought a cheaper board elsewhere & got an unmarked chip. Was not cc/cv at all. I did get a refund tho.