I noticed that a lot of entities are shifted.
This poses a big problem with adding more entities.
I think some editors have, in settings, some offset value.
Please reset the offset.

If you use Bing, set the offset to 0 for Nepal.
So far, the best is DigitalGlobe Premium Imagery with offset=0

Is there a more scientific approach to setting offset,perhaps geological survey makers visible on imagery?

According to locals, it can be a fairly good offset:

So far for Bing it is about 6.6, -5.39.
Most entities will need to be moved or re-placed.

Marek Kleciak supposes that the more precise 3 points from DGPS will be in a week.

Imagery offset can be estimated from roads with several GPS tracks, mostly H- and F-roads.
I have found Bing to be typically exact to less than 3 m.
But attention: Offset can change by dozens of meters in mountain areas because of inexact correction of slant images by insufficient elevation data (DEM model).
A strong indication of such problems are blurry parts in the imagery especially at steep mountain flanks.

There is no constant offset in any imagery.