Apktool removes boolean from static field when recompiled

Question

I am getting very strange results using Apktool in windows:

What I do:

1. I decompile the original APK file - 1.apk in cmd using this command: apktool d 1.apk

2. Then, without making any changes to any of the files, I compile the 1 folder again using this command: apktool b 1

3. Then, I decompile the new apk file 2.apk from the dist folder with this command: apktool d 2.apk

4. Lastly, I compare folders 1 and 2 and there is a a difference for some of the declared static fields:

Original decomplied file 1.apk:

.field public static savedConf:Z = false
.field public static as:Ljava/lang/String; = ""
.field public static isReady:Z = false

The recompiled and then decompiled 2.apk file:

.field public static savedConf:Z = false
.field public static as:Ljava/lang/String; = ""
.field public static isReady:Z

It is strange because the = false part in the 2.apk file is missing only for some of the static fields in several various files. Also, signing or not the 2.apk file, has no effect on the outcome.

Does anyone have an idea what might be the problem and how to fix it?

Thanks!