Hundreds of thousands of applications from veterans to enroll in the Department of Veterans Affairs healthcare system have been delayed because VA failed to reach them by mail last year.

Data provided by a VA whistleblower on Friday show that the VA tried last year to reach 494,428 veterans by mail to tell them it needed more information before their VA application could be completed.

But the data show that almost half of those letters bounced back. According to an internal VA document, 229,366 letters never reached the veterans in question, or 46 percent.

Nearly 77,000 addresses were identified by a "bad address indicator" in the VA's system. Another 54,000 letters were not accepted by software, so those letters were never sent.

And more than 98,000 letters were "undeliverable."

Scott Davis, a VA employee in Atlanta and a known whistleblower who has testified in Congress about the VA's various problems, wrote a letter to President Trump outlining the problem. Davis said the VA's problems sending letters to veterans shows that it's attempt to secure coverage for veterans is "grossly mismanaged."

He also said the document he provided shows the VA knows about these problems, but isn't talking about them. And, he said it shows that the VA shouldn't be allowed to scuttle these applications just because it failed to reach the veterans.

"The VA's own documents confirm that nearly half of the veterans who were supposed to receive notification letters didn't receive them," he wrote. "Based on this information it would be unconscionable for the administration to allow VA to go forward with their plans of purging these applications."

"Mr. president, I urge you to intervene in this matter by instructing VA to halt any plans to declare these applications abandoned and/ or incomplete," Davis wrote.

Davis issued a similar warning in February that the VA was about to improperly toss out hundreds of thousands of applications.

Read the internal VA memo here: