Used gasket lacquer for over 20 years both personally and when I had the business and only cracking problems occurred from moisture when left out afield for days on end, or when the finish was applied too thickly. Mind you am talking about the original gasket lacquer as sold by Virgil Berg of Waterloo Archery and manufactured exclusively for Virgil by the Randolf Company.
It is nitrocelleous lacquer in a thick viscosity form like that used for coatings of pencils and similar items.
Since GL/nitrocelleous lacquer is not and never has been a waterproof substance moisture can penetrate it causing the inside item-in this case a wooden dowel-to take on moisture. When wood takes on moisture it expands-when wood expands it cracks the coating on it.
Over the course of many thousands of arrows using GL I found what worked the best as far as application. Sure it is more work but a better finish was obtained. GL in the form as it comes/came from the can in my case was way too thick-too thick to pour decently-too thick to insert shaft into and withdraw shaft from it so I started experimenting with thinning it. I had known for a long time that multiple thin coats of any paint ar better than 1 or 2 thick coats and that there was a cure time between coats.
First started thinning with acetone and lacquer thinner to get a consistency like syrup and then applying 5-9 coats(steel wooling between every 2-3 coats) of this thinner finished with appropiate drying/curing time between finishes which produced much better results.
Then later I found gallon cans of Nitrocelleous lacquer at the local big box store-think it was Home Depot but could have been Lowes-this was back in the mid 1990's and do not know if they have it now. Would take this thinner NL and thin the thicker GL with it to the consistencly of syrup and it produced an even better finish again using 5-7 coats(steel wooling between every 2-3 coats) with ample drying/curing time in between coats. The last 2 coats were only put on after at least a 24 hour cure time and the resulting finsh prooved tougher than before. Thereafter that is how I produced all the arrows I sold and used myself.
Were they waterproof-no but they lasted a long time under normal wear and tare. This normal wear and tare does not include being left outside in moist conditions like lost in the vegatation, etc.
If your desires are for a waterproof finish that can be used in wet environments then GL or NL would not be my choice. If your only requirement is for the finish to provide prirection while normal shooting and practice, plus bowhunting where one always brings the arrows indoors after each and every use outside then a GL/NL mix applied as directed above will do a good job.