One of the longest-running ticks against Sony's A7 line is its lossy compression of RAW files. DPReview puts the issue in layman's terms:
“These approaches probably made sense in consumer-grade cameras, back in the days where processing power and storage space came at a significant premium. However, on a camera as expensive as the a7R II, which is likely to be used for quality-critical shooting, it’s hard to justify clumsy compression that can, depending on the image, throw away data you were expecting to have access to.”