Differences in BRepTools serialization/deserialization from 7.5 -> 7.6

In my application I use BRepTools.Write() and BRepTools.Read() to serialize TopoDS_Shape instances to file.

I have found some differences in the behavior of this method when upgrading from OpenCASCADE 7.5 to 7.6. I would expect that if I use BRepTools.Write/Read to serialize and deserialize objects to string as follows:

shape_1 -> string_1 -> shape_2 -> string_2

then string_1 and string_2 would be equal.

With OCCT 7.6, this fails on some shapes where OCCT 7.5 would pass.

As an example, here is a snippet using the OCP bindings in Python.

import io
from OCP import BRepPrimAPI, gp, BRepTools, TopoDS, BRep


def dump(shape):
    b = io.BytesIO()
    BRepTools.BRepTools.Write_s(shape, b)
    return b.getvalue().decode('utf-8')


def load(s):
    shape = TopoDS.TopoDS_Shape()
    builder = BRep.BRep_Builder()
    b = io.BytesIO(bytes(s, 'utf-8'))
    BRepTools.BRepTools.Read_s(shape, b, builder)
    return shape


pnt = gp.gp_Pnt(1, 0, 0)
shape_1 = BRepPrimAPI.BRepPrimAPI_MakeSphere(pnt, 1.0).Shape()

# serialize
ser_1 = dump(shape_1)

# deserialize
shape_2 = load(ser_1)

# serialize again
ser_2 = dump(shape_2)

with open('ser_1-7.5.3.txt', 'w') as f:
    f.write(ser_1)

with open('ser_2-7.5.3.txt', 'w') as f:
    f.write(ser_2)

# make sure serialization is the same
assert ser_1 == ser_2

With OCCT 7.5.3, ser_1 == ser_2, while with OCCT 7.6.3 ser_1 != ser_2.

The difference is small - the "checked" bit of the shell entity is flipped.

Is this expected? What is the significance of the "checked" bit?

I also experience the same issue with BinTools, although it is harder to read the output.