I went to the trader’s area in Stormwind, picked up only 200 trader tender from the box (should have been more than that) then talked to the npc and it’s showing I only have 50 tender. Something is amiss!
Hope you’re having a good day and hope I’m alone in experiencing this buggy bug.
I had ~1375 tender last night before I logged off, and now the game is telling me I have none.
I’m also out an extra thousand from my pre-order purchase on top of that.
Edit:
Should add, I didn’t even interact with the trading post in the game world, just looked at the interface after I logged on and saw that it said I had nothing.
Edit 2:
I got my original 1375 tender back, but still have yet to receive my 1000 tender bonus for the pre-order.
Edit 3:
Turns out it was in the chest at the Trading Post waiting for me.
I was just too paranoid to go open it and take a look, thinking I would only get the 1k from the monthly and be denied due recompense.
Oh my gosh! Please tell me this will be fixed! I had close to 10,000 trading tenders, and also now showing 0 after having purchased mount that did not show in inventory and producing LUA errors and refunding. This is very concerning, would greatly appreciate a Blue Response ASAP.
Same issue here after small update this afternoon - didn’t have a ton still but enough to notice it missing (plus the 500 for visiting the post)
Hope this is resolved soon. 
Also seeming a bit short on my end, swore I had 2100~ roughly before I did my trading post tasks, after buying the items I wanted. Once I finished my tasks and went to collect my tenders, I am now sitting at 1815.
Re-counting several times with my napkin math skills, all seems to be accounted for, think in my case I just had assumed I hadn’t spent as much as I did. At least in my case.
I show having zero travel points for this month, but several parts have been completed. I don’t even want to check my trader’s tender that has accumulated over the months.
This is generally an in-game display bug; you can find your correct amount in your accounts virtual wallet under transaction history.
It’s still a bug because my wallet also says only 50 coins, how would I have only 50 when I haven’t purchased anything this month? I’ve been subbed the whole time also.
Something is fishy!~
If it says you have 50, you only have 50. Check your detailed transaction history for what you spent/gained.
That makes no sense though. Why did I not get my monthly tender? I was subbed the whole time. I clicked the chest, it said I collected 200 (which sounds about right for the remaining tasks I had done, but not the monthly) and then when clicking the vendor it says 50. Not sure why people are convinced this isn’t a bug considering how many other bugs this patch is having 
50 is how much I had when I completed my last transaction at the vendor, since then I had completed more tasks, and a new month rolled over (day of post) so I should absolutely have more than 50 tender now.
This is why I said check your transaction history (as a means to verify you actually gained the 200).