I built a website in Drupal that uses a node type with an abundance of fields. Its purpose is for listing different types of local food suppliers that fell into other areas such as tours, activities and so forth. The nodes had so many fields because the owner's of the site wanted to attach a lot of different data pieces to each listing so they can track when they signed up, paid for print listing, how they paid, etc. This is in addition to all the data fields the site visitor would be interested in while browsing these members.
A huge majority of the existing data was exported from their site's previous incarnation and reimported using Drupal Feeds. Once that was done their team went to work adding new member listings and also functionality was put in place for new members to sign up and add their listings.
Everything seemed fine until they went to update certain listings and something extremely odd happened. Upon clicking Save after editing the nodes their screen refreshed and just loaded the node editor again without any of their changes being saved. There was no discernible error or any indication that something went wrong. Watchdog didn't log anything nor were there any server errors to look to.
I did a lot of searching to see if anyone else had this problem. The closest I found were some people who had a problem saving but because of permissions vs. the import format they were forbidden to update. I have actually experienced that particular problem before so I knew this wasn't it.
I figured out an interim workaround but you need to have Administration Views installed for this to work. Find the node in /admin/content and click the checkbox next to the title then choose Change Value under Operations. In the next screen click the checkbox next to the field or fields you need to update. Take care that if your field has multiple checkboxes or any other data you don't lose it. This editor gives you a blank slate on the field you choose.
An actual fix to the bug was still in order so I proceeded to try to narrow down what was causing the fault. Not every node was behaving this way so logically I had to figure out what was the difference between ones that would save and those that would not. I mentioned there were a lot of fields. About 65 fields. Some of them were multiple select fields that ranged between 10 and 30 items. Based on this post: http://2bits.com/drupal/drupal-not-saving-admin-pages-large-number-input... I was guessing that there were too many fields and I was overloading max_input_vars in PHP. I tried first to change that in a php.ini file but ended up getting a 500 server error for my trouble. I then tried a live chat with the host's technical support to figure out if that was what was happening. All he could find was some php error relating to recaptcha and a Wordpress security mod. He was going to deactivate Mod Security for me. That didn't seem like a good idea so I just told him I was going to put this problem aside for now and come back to it later. What I ended up doing was working with a dev version of the site I cleared out all of the fields on one of the nodes that I knew was causing the problem. I then proceeded to add back one field at a time the data comparing it to the live site. Saving each time I put in a new value and watching to see if it replicated the fault. All the way at the bottom of the form there was a select option field that had one value: Kid's Activities/And Or Events. When checked in the node editor it refreshed without updating.
So what I had was a List (text) field with check boxes of multiple options one of which had an apostrophe. I tried simply to overwrite it in the Manage Fields editor but drupal wouldn't let me, and rightly so. I added a new value without the apostrophe, created a view to find all the nodes that used the original bad value then corrected all of them manually and once no nodes had that value I was able to remove it from the list of options.
Now their nodes can be happily updated without any wierd edit page refresh.