There was an issue when importing a cell with GDS database unit of 5E-6 microns to a GDS cell with a standard database unit of 1E-3 microns. In Klayout I tried growing everything by 1nm then shrinking by 1nm in order to merge polygons in the same waveguide, and then resaving with a database unit of 1E-3. The length error per asymmetric Mach Zehnder is inconsistent, ranging from 0.017nm up to 5.3nm, while before performing these operations all the errors were less than 0.25nm. So this issue is still not solved. Any feedback would be greatly appreciated.