Please review the Q&A Usage Guidelines before posting, specifically point 3, "Quote the applicable rule from the latest version of the manual in your question".
In this case, the applicable rule is SG5, quoted below, with a portion bolded for emphasis.
<SG5> Enter the Neutral Zone during Autonomous at your own risk. Any Robot who engages with the Neutral Zone during the Autonomous Period should be aware that opponent Robots may also choose to do the same. Per <G11> and <G12>, Teams are responsible for the actions of their Robots at all times.
a. For the purposes of this rule, “engages with” means any combination of:
i. Contacting foam tiles within the Neutral Zone
ii. Contacting Neutral Mobile Goals
iii. Contacting Rings that begin the Match on the double white tape line in the center of the Neutral Zone
b. If opposing Robots contact one another while both engaging with the Neutral Zone, and a possible <G12> violation results (i.e. damage, Entanglement, or tipping over), then a judgment call will be made by the Head Referee within the context of <G12> just as it would if the interaction had occurred during the Driver Controlled Period.
c. If opposing Robots contact one another while both engaging with the Neutral Zone, **and an incidental violation of <SG4> occurs, **no penalty will be assessed on either Alliance.
d. <G15> does not apply during the Autonomous Period.
e. Intentional, strategic, repeated, or egregious offenses of points “b” or “c” may still be deemed a violation of <SG4>, <G12>, <G13>, <G14>, <G1>, and / or <S1> at the Head Referee’s discretion.
As well as the following portion of the "red box" underneath SG5:
The Neutral Zone is intended to be a zone that Robots from both Alliances can utilize during the Autonomous Period. This will inevitably result in Robot-on-Robot interactions, both incidental and intentional. The overarching intent of <SG5> is for the vast majority of these interactions to result in no rule violations and / or penalties for either Alliance, just as no rules violations occur in 99% of Driver Controlled interactions.
So, with those quotes in mind...
if two robots grab a goal and the Red robot pulls the Blue robot across the alliance line.
is this a violation for the Blue robot?
This sounds like an incidental violation of SG4. Therefore, point "c" would apply, and no penalty would be assessed on either Alliance.
But what if the Blue robot still in auton then Disables the Red robot? Is there any penalty by either robot?
This sounds like a possible violation of G12. Therefore, point "b" would apply, and the Head Referee will make a judgment call within the context of G12 just as if the interaction had occurred during the Driver Controlled Period. In most cases, this would be considered "no violation".
As stated in G11, G12, and SG5, Teams are responsible for the actions of their Robot at all times. Robots who choose to engage with the Neutral Zone during the Autonomous Period should be aware that opponent Robots may also choose to do the same, and prepare for the risks associated with doing so.