Those with lagging data, do you have adequate system CPU/RAM/bandwidth resources? For high trade-rate symbols at busy times on layouts having many charts, multiple complex EFS formulas, or quote windows with many symbols, the CPU can regularly hit 100% utilization. Also, the data throughput demands can exceed the available internet connection bandwidth. Also, lack of available RAM can be an issue. At 100% CPU, the charts will only update as the processor queue clears. In the case of insufficient system resources, it gives the appearance of data lag on the layout windows.
CPU/RAM/bandwidth limitations might not be the cause of the specific lag you're talking about, but I thought I'd mention it as something to check.