For the third time since their January launch, spot Bitcoin ETFs witnessed net outflows last week as Bitcoin (CRYPTO: BTC) prices declined 8% last week. What Happened: BitMEX Research data, as reported by Blockworks, indicates an $83 million drop in assets in the 11-fund category from April 8 to April 12. This is a stark contrast to the net inflows of $485 million recorded the previous week. Since their launch on January 11, spot Bitcoin ETFs have collectively attracted $12.5 billion in positive flows. However, the Grayscale Bitcoin Trust ETF (OTC:GBTC) has been the only U.S. BTC fund to consi…