Problems with IF Statements

I'm having lots of problems with code being lost after inputting it, then clicking OK. I don't understand why parts of the code are lost.

Here are some examples. Can anyone help with this?

With this test example, all is lost except "let":

Let text1 := City;
if Address2 = null then
if Country != null then
Country
End;
end

With this test example:

if Address2 = null then
Let text1 := Country;
if Country != null then text1; End;
else
Let text1 := City;
if State != null then
text1 := text1 + ", " + State
end;
if Zip != null then
text1 := text1 + " " + Zip
end;
text1
end;

This is all is all that remains, when clicking OK:

if Address2 = null then Let end

When entering this formula:

if Address2 = null then
if Country != null then Country end
Else
City + ", " + State + " " + Zip
end

this is the code after clicking OK; lines 3 and 4 were gone:

if Address2 = null then
if Country != null then Country end
end

When entering this formula:

if Address2 = null then
if Country != null then Country end
Else City + ", " + State + " " + Zip
end

After clicking OK, this is all that remains:

if Address2 = null then
if Country != null then Country end
end