I see the same thing, after updating to 2.1.8L0 Never had any problems like this on previous firmware. I'll continue to use 2.1.8L0 as I want to get a feel for the SQ, as long as the problems like this happen infrequently, and I can live with the odd occurence. If it get's worse, or becomes bothersome, I suppose the answer is to switch back to 2.1.5 and wait for 2.1.8 to be fixed with a new version.
On a positive note, I am happy to see that new firmware can provide improvements to the SQ, as it gives hope that there are more improvements ahead.
I would also suggest that iBasso focus the current engineering resources on fixing up the interface problems. Let the engineers focus on that, and delay adding any more features, even if this results in some unhappiness from users. Introducing more features adds more variables, and complexity, versus working with the current feature set, and just focusing on fixing the interface issues. And if there is a choice, I believe most people will be happier with a working DAP with less features, rather than having many features, with a DAP that becomes irritating and unusable. I believe the majority of users want, and use the DX90 as a portable DAP, whose main purpose is to play music well. It is icing on the cake if it also does a good job as a desktop replacement, an audio decoder for Videos, an external DAC, etc., but that is not it's main purpose, or what it was designed for. Doing one thing really well, is preferable to doing many things not very well.
Utilizing what it can do, I am finding that using the LO to drive an external amp/speakers sounds better than using JRiver on a PC, to a Micromega MyDac as the front end. Using the same amp, just swapping between the DX90 LO, versus the MyDac LO.
