In this article, we will discuss why some signatures are not rendered correctly.
Why does my email signature get messed up in some reply emails?
Unfortunately, we cannot control what the email signatures look like after someone replies to our emails. That's because once the signature leaves from the email client, there are so many other factors that can affect the signature, that we cannot control.
When the signature arrives in the recipient's email client and is read by the recipient, it should look as it's intended to look* because that recipient is in "reading mode".
But as soon as that recipient hits reply to your email, the recipient's email client has just shifted into "composing mode". The user and the user's email client can now alter your HTML signature however they like or need.
There is no solution or workaround for this when using HTML email signatures. It's just the way that some email clients work.
For example -
If your recipient is using Gmail, expect basic line spacing variance in the signature of the email that is sent. This is due to the limitation Gmail has on how they render and choose to display the signature.
You can notice the difference in the way Gmail has added space b/w words. 
If your recipient is using Outlook or, expect images to have size variance in the signature of the email that is sent. This is due to the limitation Outlook has on how they render and choose to display images for the signature
Different email clients (ie. Microsoft, Yahoo, etc.) may render and display your email signature differently.
Because of this, how your signature is displayed depends on where the email is received.