This past December the following exported with no problem (I have not 
exported a table of any type since then)

* TestTableExport :ignoreheading:
:PROPERTIES:
:EXPORT_FILE_NAME: /mnt/Data/ActiveFiles/testthetable
:END:


#+LATEX_COMPILER: pdflatex
#+LATEX_CLASS: koma-article
#+LATEX_CLASS_OPTIONS: 
[letterpaper.twoside=false,fontsize=11pt,DVI=15,parskip=half,parindent=1.2cm,headings=small]
#+LATEX_HEADER: \usepackage{verbatim}
#+LATEX_HEADER: \usepackage[T1]{fontenc}
#+LATEX_HEADER: \usepackage[math]{anttor}
#+LATEX_HEADER: \usepackage[utf8]{inputenc}
#+LATEX_HEADER: \usepackage{charter}
#+LATEX_HEADER: \usepackage{calc}
#+LATEX_HEADER: \usepackage{setspace}
#+LATEX_HEADER: \usepackage{layout}
#+LATEX_HEADER: \usepackage{array}
#+LATEX_HEADER: \usepackage{graphicx}
#+LATEX_HEADER: \usepackage{tabulary}
#+LATEX_HEADER: \usepackage{longtable}
#+LATEX_HEADER: \usepackage{numprint}
#+LATEX_HEADER: \npstyleenglish
#+LATEX_HEADER: \npthousandthpartsep{}
# #+LATEX_HEADER: \usepackage{siunitx}
# #+LATEX_HEADER: 
\sisetup{group-separator={,},group-minimum-digits={3},output-decimal-marker={.},table-number-alignment=right}
#+LATEX_HEADER: 
\usepackage[at]{easylist}{\ListProperties(Hang1=False,Indent1=1.2cm)}
#+LATEX_HEADER: \usepackage{csquotes}
# #+LATEX_HEADER: 
\usepackage[letterpaper,left=1.00in,right=1.00in,top=1.00in,bottom=1.00in]{geometry}
#+LATEX_HEADER: \pagenumbering{arabic}
#+LATEX_HEADER: \usepackage{lastpage}
#+LATEX_HEADER: \usepackage{scrlayer-scrpage}
#+LATEX_HEADER: \pagestyle{scrheadings}
#+LATEX_HEADER: \setkomafont{pagefoot}{\normalfont\rmfamily}
#+LATEX_HEADER: \cfoot[\pagemark]{\thepage}
# latex headers for this file only
#+LATEX_HEADER: \ifoot{Rita A. Sator Estate}
#+MACRO: cm2space @@latex:\ \ @@
#+MACRO: cmbcenter @@latex:\begin{center}@@
#+MACRO: cmecenter @@latex:\end{center}@@
#+MACRO: cmhfill @@latex:\hspace\fill@@



#+ATTR_LATEX: :mode table :environment longtable :align 
p{20pt}p{200pt}p{60pt)p{60pt}
| 1. | Verizon inventory value upon sale      |           | |
|    | Date                                   |           | |
|    | received 2016-12-14                    |           | 3142.77 |
|    | reinvested dividend 2015-02-01         |  1.341086 |   51.15 |
|    | reinvested dividend 2015-05-01         |  2.793883 |  113.59 |
|    | reinvested dividend 2016-02-03         |  1.532931 |   51.24 |
|    | Total                                  |           | |
|    |                                        |           | |
| 2. | Vodafone PLC inventory value upon sale |           | |
|    | Date                                   |           | |
|    | received 2016-12-14                    | 94.910515 | 3142.77 |
|    | reinvested dividend 2015-02-05         |  1.341086 |   51.15 |
|    | reinvested dividend 2015-08-06         |  2.793883 |  113.59 |
|    | reinvested dividend 2016-02-03         |  1.532931 |   51.24 |
|    | Total                                  | 99.678415 | 3358.75 |
|    |                                        |           | |

#+ATTR_LATEX: :mode table :environment longtable :align p{20pt}p{350pt}
| 3. | lost of stuff for this note           |
| 4. | more information for full disclosure  |
|    |                                       |
\newpage

my init has the following

(add-to-list 'org-latex-classes
                  '("koma-article"
"\\documentclass{scrartcl}
\\newcommand{\\foo}{bar}
[NO-DEFAULT-PACKAGES]
[NO-PACKAGES]
[EXTRA]"
("\\section{%s}" . "\\section*{%s}")
("\\subsection{%s}" . "\\subsection*{%s}")
("\\subsubsection{%s}" . "\\subsubsection*{%s}")
("\\paragraph{%s}" . "\\paragraph*{%s}")
("\\subparagraph{%s}" . "\\subparagraph*{%s}")))

Today the four column table does not export; the two column table (items 
labeled 3 and 4) does export; . Please see the attached report.

Org mode version 9.0.5 (release_9.0.5-444-g998576.dirty @ 
/usr/local/share/emacs/site-lisp/org-mode/lisp/)
GNU Emacs 24.4.1 (x86_64-pc-linux-gnu, GTK+ Version 3.14.5) of 
2015-03-07 on trouble, modified by Debian

If I remove the last two columns in the four column table and also 
remove the last aligns, i.e. p{60pt}, the first table then exports as 
two columns.

THEN, for the first table I re-enter the two p{60pt} and also insert the 
last two columns, with numbers, it exports as expected.